small fixes + debug

testing

.github/workflows/maven.yml

@@ -0,0 +1,104 @@
+name: Java CI with Maven
+
+on:
+  workflow_dispatch:
+  push:
+    branches: [ "dev", "cleanup" ]
+    tags:
+      - 'v*.*.*'
+  pull_request:
+    branches: [ "main" ]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+    - name: Set up JDK 17
+      uses: actions/setup-java@v4
+      with:
+        java-version: '17'
+        distribution: 'temurin'
+        cache: maven
+    - name: Build with Maven
+      run: mvn -B package
+      working-directory: main
+    - name: Upload built JAR
+      uses: actions/upload-artifact@v4
+      with:
+        name: package
+        path: main/target/*.jar
+    - name: Generate dependency graph
+      run: mvn -B -f main/pom.xml com.github.ferstl:depgraph-maven-plugin:4.0.1:graph
+    - name: Upload dependency graph artifact
+      uses: actions/upload-artifact@v4
+      with:
+        name: dependency-graph
+        path: main/target/**
+
+  build-windows:
+    runs-on: windows-latest
+    steps:
+    - uses: actions/checkout@v4
+    - name: Set up JDK 17
+      uses: actions/setup-java@v4
+      with:
+        java-version: '17'
+        distribution: 'temurin'
+        cache: maven
+    - name: Build with Maven (Skip Tests)
+      run: mvn -B package -DskipTests
+      working-directory: main
+    - name: Create JPackage App Image
+      shell: pwsh
+      run: |
+        New-Item -ItemType Directory -Force -Path "dist"
+        jpackage --name "DTSS" `
+          --input main/target `
+          --main-jar main-1.0-SNAPSHOT.jar `
+          --dest dist `
+          --type app-image `
+          --win-console
+    - name: Inject java.exe
+      shell: pwsh
+      run: |
+        $javaPath = (Get-Command java).Source
+        Copy-Item -Path $javaPath -Destination "dist/DTSS/runtime/bin/"
+    - name: Zip Windows Release
+      shell: pwsh
+      run: |
+        Compress-Archive -Path "dist/DTSS" -DestinationPath "dist/DTSS-Windows.zip"
+    - name: Upload Windows Artifact
+      uses: actions/upload-artifact@v4
+      with:
+        name: windows-package
+        path: dist/DTSS-Windows.zip
+
+  publish-release:
+    runs-on: ubuntu-latest
+    needs: [build, build-windows]
+    if: startsWith(github.ref, 'refs/tags/') || github.event_name == 'workflow_dispatch'
+    permissions:
+      contents: write
+    steps:
+    - name: Download Linux JAR
+      uses: actions/download-artifact@v4
+      with:
+        name: package
+        path: main/target/
+    - name: Download Windows Zip
+      uses: actions/download-artifact@v4
+      with:
+        name: windows-package
+        path: windows-dist/
+    - name: Create GitHub Release
+      uses: softprops/action-gh-release@v2
+      with:
+        tag_name: ${{ startsWith(github.ref, 'refs/tags/') && github.ref_name || 'snapshot-build' }}
+        name: ${{ startsWith(github.ref, 'refs/tags/') && github.ref_name || 'Manual Snapshot Build' }}
+        draft: false
+        prerelease: true
+        make_latest: false
+        files: |
+          main/target/*.jar
+          windows-dist/*.zip

.gitignore

@@ -48,3 +48,6 @@ build/
 # Other
 *.swp
 *.pdf
+
+# JAR built pom file
+dependency-reduced-pom.xml

README.md

@@ -0,0 +1,620 @@
+# Sistema de Simulação de Tráfego Distribuído
+
+Sistema distribuído de simulação de tráfego.
+---
+
+## Índice
+
+- [Visão Geral](#visão-geral)
+- [Arquitetura](#arquitetura)
+- [Protocolo de Comunicação](#protocolo-de-comunicação)
+- [Estrutura do Projeto](#estrutura-do-projeto)
+- [Instalação e Execução](#instalação-e-execução)
+- [Documentação](#documentação)
+- [Desenvolvimento](#desenvolvimento)
+
+---
+
+## Visão Geral
+
+Este projeto implementa uma simulação distribuída de tráfego veicular numa rede de cruzamentos. O sistema utiliza:
+
+- **Processos independentes** para cada cruzamento
+- **Threads** para controlar os semáforos dentro de cada cruzamento
+- **Comunicação via sockets** para transferência de veículos entre cruzamentos
+- **Simulação de eventos discretos** (DES) para gerir o tempo de simulação
+
+### Características Principais
+
+- Simulação determinística e reproduzível
+- Comunicação assíncrona entre processos
+- Protocolo de mensagens baseado em JSON
+- Dashboard em tempo real (planeado)
+- Estatísticas detalhadas de desempenho
+
+---
+
+## Arquitetura
+
+### Visão Geral do Sistema
+
+```
+┌─────────────────────────────────────────────────────────────────┐
+│                    SISTEMA DISTRIBUÍDO                           │
+├─────────────────────────────────────────────────────────────────┤
+│                                                                   │
+│  ┌──────────────┐                          ┌──────────────┐     │
+│  │  Coordenador │ ────────────────────────>│  Dashboard   │     │
+│  │  / Gerador   │                          │              │
+│  └──────┬───────┘                          └──────▲───────┘     │
+│         │                                          │             │
+│         │ Gera veículos                    Stats  │             │
+│         │                                          │             │
+│         ▼                                          │             │
+│  ┌─────────────────────────────────────────────────┴──────┐     │
+│  │          Rede de Cruzamentos (Processos)              │     │
+│  │                                                         │     │
+│  │  ┌────┐         ┌────┐         ┌────┐                 │     │
+│  │  │Cr1 │◄───────►│Cr2 │◄───────►│Cr3 │                 │     │
+│  │  └─┬──┘         └─┬──┘         └─┬──┘                 │     │
+│  │    │              │              │                     │     │
+│  │    │         ┌────▼────┐         │                     │     │
+│  │    └────────►│   Cr4   │◄────────┘                     │     │
+│  │              └────┬────┘                               │     │
+│  │                   │                                     │     │
+│  │              ┌────▼────┐                               │     │
+│  │              │   Cr5   │                               │     │
+│  │              └────┬────┘                               │     │
+│  └───────────────────┼─────────────────────────────────────┤     │
+│                      │                                     │     │
+│                      ▼                                     │     │
+│               ┌──────────────┐                            │     │
+│               │  Nó de Saída │                            │     │
+│               │      (S)     │                            │     │
+│               └──────────────┘                            │     │
+│                                                            │     │
+└────────────────────────────────────────────────────────────┘     │
+```
+
+### Componentes
+
+1. **Coordenador/Gerador**: Gera veículos e injeta no sistema
+2. **Cruzamentos (Cr1-Cr5)**: Processos independentes que gerem tráfego local
+3. **Nó de Saída (S)**: Recolhe estatísticas de veículos que saem do sistema
+4. **Dashboard Server**: Agrega e exibe dados em tempo real
+
+---
+
+## Protocolo de Comunicação
+
+### Formato de Serialização: JSON (Gson)
+
+O sistema utiliza JSON como formato de serialização por ser mais rápido, seguro e legível que a serialização em Java.
+
+### Estrutura de Mensagens
+
+Todas as mensagens seguem o formato base:
+
+```json
+{
+  "messageId": "uuid",
+  "type": "MESSAGE_TYPE",
+  "senderId": "sender_id",
+  "destinationId": "destination_id",
+  "timestamp": 1729595234567,
+  "payload": { ... }
+}
+```
+
+### Tipos de Mensagens
+
+#### 1. VEHICLE_TRANSFER
+
+Transfere um veículo entre cruzamentos.
+
+**Estrutura:**
+```json
+{
+  "messageId": "a3c5e7f9-1234-5678-90ab-cdef12345678",
+  "type": "VEHICLE_TRANSFER",
+  "senderId": "Cr1",
+  "destinationId": "Cr2",
+  "timestamp": 1729595234567,
+  "payload": {
+    "id": "V123",
+    "type": "LIGHT",
+    "entryTime": 15.7,
+    "route": ["Cr1", "Cr2", "Cr5", "S"],
+    "currentRouteIndex": 1,
+    "totalWaitingTime": 3.2,
+    "totalCrossingTime": 1.8
+  }
+}
+```
+
+**Fluxo:**
+1. Veículo completa travessia no Cr1
+2. Cr1 serializa mensagem VEHICLE_TRANSFER
+3. Envia para Cr2 via socket
+4. Cr2 desserializa e adiciona veículo à fila
+
+#### 2. STATS_UPDATE
+
+Envia estatísticas de um cruzamento para o Dashboard.
+
+**Estrutura:**
+```json
+{
+  "messageId": "b4d6e8f0-2345-6789-01bc-def123456789",
+  "type": "STATS_UPDATE",
+  "senderId": "Cr3",
+  "destinationId": "Dashboard",
+  "timestamp": 1729595234789,
+  "payload": {
+    "intersectionId": "Cr3",
+    "queueLengths": {
+      "North": 5,
+      "South": 3,
+      "East": 7,
+      "West": 2
+    },
+    "vehiclesProcessed": 142,
+    "averageWaitTime": 4.5,
+    "currentTime": 123.45
+  }
+}
+```
+
+**Frequência:** A cada 10 segundos (configurável)
+
+#### 3. VEHICLE_EXIT
+
+Notifica quando um veículo sai do sistema.
+
+**Estrutura:**
+```json
+{
+  "messageId": "c5e7f9a1-3456-7890-12bc-def123456789",
+  "type": "VEHICLE_EXIT",
+  "senderId": "Cr5",
+  "destinationId": "ExitNode",
+  "timestamp": 1729595234890,
+  "payload": {
+    "id": "V123",
+    "type": "LIGHT",
+    "entryTime": 15.7,
+    "exitTime": 45.2,
+    "totalSystemTime": 29.5,
+    "totalWaitingTime": 8.3,
+    "totalCrossingTime": 4.8,
+    "routeTaken": ["Cr1", "Cr2", "Cr5", "S"]
+  }
+}
+```
+
+#### 4. HEARTBEAT
+
+Mantém a ligação ativa e monitoriza a saúde dos processos.
+
+**Estrutura:**
+```json
+{
+  "messageId": "d6e8f0a2-4567-8901-23cd-ef1234567890",
+  "type": "HEARTBEAT",
+  "senderId": "Cr1",
+  "destinationId": "Coordinator",
+  "timestamp": 1729595235000,
+  "payload": {
+    "status": "RUNNING",
+    "uptime": 120.5,
+    "vehiclesInQueue": 12
+  }
+}
+```
+
+**Frequência:** A cada 5 segundos
+
+#### 5. LIGHT_CHANGE
+
+Notifica mudança de estado de semáforo (para logging/debugging).
+
+**Estrutura:**
+```json
+{
+  "messageId": "e7f9a1b3-5678-9012-34de-f12345678901",
+  "type": "LIGHT_CHANGE",
+  "senderId": "Cr1-North",
+  "destinationId": "Dashboard",
+  "timestamp": 1729595235100,
+  "payload": {
+    "lightId": "Cr1-North",
+    "previousState": "RED",
+    "newState": "GREEN",
+    "queueSize": 5
+  }
+}
+```
+
+### Tipos de Veículos
+
+```json
+{
+  "BIKE": {
+    "probability": 0.20,
+    "crossingTime": 1.5
+  },
+  "LIGHT": {
+    "probability": 0.60,
+    "crossingTime": 2.0
+  },
+  "HEAVY": {
+    "probability": 0.20,
+    "crossingTime": 4.0
+  }
+}
+```
+
+### Estados dos Semáforos
+
+```
+RED    → Veículos aguardam na fila
+GREEN  → Veículos podem atravessar
+```
+
+### Exemplo de Comunicação Completa
+
+```
+Tempo    Processo    Ação                                    Mensagem
+------   ---------   -------------------------------------   ------------------
+15.7s    Gerador     Gera veículo V123                      -
+15.7s    Gerador →   Injeta V123 em Cr1                     VEHICLE_TRANSFER
+18.2s    Cr1         V123 inicia travessia                  -
+20.2s    Cr1         V123 completa travessia                -
+20.2s    Cr1 → Cr2   Transfere V123 para Cr2                VEHICLE_TRANSFER
+23.5s    Cr2         V123 inicia travessia                  -
+25.5s    Cr2         V123 completa travessia                -
+25.5s    Cr2 → Cr5   Transfere V123 para Cr5                VEHICLE_TRANSFER
+28.0s    Cr5         V123 inicia travessia                  -
+30.0s    Cr5         V123 completa travessia                -
+30.0s    Cr5 → Exit  V123 sai do sistema                    VEHICLE_EXIT
+30.0s    Exit → Dash Estatísticas de V123                   STATS_UPDATE
+```
+
+---
+
+## Estrutura do Projeto
+
+```
+Trabalho-Pratico-SD/
+├── README.md                          # Este ficheiro
+├── TODO.md                            # Plano de desenvolvimento
+├── main/
+│   ├── pom.xml                        # Configuração do Maven
+│   ├── docs/
+│   │   ├── README.md                  # Índice da documentação
+│   │   ├── SERIALIZATION_SPECIFICATION.md
+│   │   ├── SERIALIZATION_DECISION.md
+│   │   ├── SERIALIZATION_SUMMARY.md
+│   │   └── SERIALIZATION_ARCHITECTURE.md
+│   ├── src/
+│   │   ├── main/java/sd/
+│   │   │   ├── Entry.java             # Ponto de entrada
+│   │   │   ├── config/
+│   │   │   │   └── SimulationConfig.java
+│   │   │   ├── engine/
+│   │   │   │   └── SimulationEngine.java
+│   │   │   ├── model/
+│   │   │   │   ├── Event.java
+│   │   │   │   ├── EventType.java
+│   │   │   │   ├── Intersection.java
+│   │   │   │   ├── Message.java          # Estrutura de mensagens
+│   │   │   │   ├── MessageType.java      # Tipos de mensagens
+│   │   │   │   ├── TrafficLight.java
+│   │   │   │   ├── Vehicle.java
+│   │   │   │   └── VehicleType.java
+│   │   │   ├── serialization/            # Sistema de serialização
+│   │   │   │   ├── MessageSerializer.java
+│   │   │   │   ├── SerializationException.java
+│   │   │   │   ├── JsonMessageSerializer.java
+│   │   │   │   ├── SerializerFactory.java
+│   │   │   │   ├── SerializationExample.java
+│   │   │   │   └── README.md
+│   │   │   └── util/
+│   │   │       ├── RandomGenerator.java
+│   │   │       ├── StatisticsCollector.java
+│   │   │       └── VehicleGenerator.java
+│   │   └── test/java/
+│   │       ├── SimulationTest.java
+│   │       └── sd/serialization/
+│   │           └── SerializationTest.java
+│   └── target/                        # Ficheiros compilados
+└── .vscode/                           # Configuração do VS Code
+```
+
+---
+
+## Instalação e Execução
+
+### Pré-requisitos
+
+- **Java 17** ou superior
+- **Maven 3.8+**
+- **Git**
+
+### Instalação
+
+```bash
+# Clonar o repositório
+git clone https://github.com/davidalves04/Trabalho-Pratico-SD.git
+cd Trabalho-Pratico-SD/main
+
+# Compilar o projeto
+mvn clean compile
+
+# Executar os testes
+mvn test
+```
+
+### Execução
+
+#### Simulação Básica (Single Process)
+
+```bash
+mvn exec:java -Dexec.mainClass="sd.Entry"
+```
+
+#### Exemplo de Serialização
+
+```bash
+mvn exec:java -Dexec.mainClass="sd.serialization.SerializationExample"
+```
+
+#### Configuração
+
+Editar `src/main/resources/simulation.properties`:
+
+```properties
+# Duração da simulação (segundos)
+simulation.duration=60.0
+
+# Modelo de chegada: FIXED ou POISSON
+arrival.model=POISSON
+
+# Taxa de chegada (veículos/segundo)
+arrival.rate=0.5
+
+# Intervalo de atualização de estatísticas (segundos)
+stats.update.interval=10.0
+
+# Distribuição de tipos de veículos
+vehicle.type.bike.probability=0.20
+vehicle.type.light.probability=0.60
+vehicle.type.heavy.probability=0.20
+
+# Tempos de travessia por tipo (segundos)
+vehicle.type.bike.crossing.time=1.5
+vehicle.type.light.crossing.time=2.0
+vehicle.type.heavy.crossing.time=4.0
+```
+
+---
+
+## Documentação
+
+### Documentação de Serialização
+
+A documentação completa sobre o protocolo de serialização está disponível em:
+
+- **[Índice Completo](./main/docs/README.md)** - Navegação da documentação
+- **[Especificação](./main/docs/SERIALIZATION_SPECIFICATION.md)** - Design detalhado
+- **[Guia de Decisão](./main/docs/SERIALIZATION_DECISION.md)** - Porquê JSON?
+- **[Resumo](./main/docs/SERIALIZATION_SUMMARY.md)** - Estado de implementação
+- **[Arquitetura](./main/docs/SERIALIZATION_ARCHITECTURE.md)** - Diagramas visuais
+
+### Guias de Utilização
+
+- **[Serialization README](./main/src/main/java/sd/serialization/README.md)** - Como utilizar os serializers
+
+### Exemplos de Código
+
+```java
+// Criar serializer
+MessageSerializer serializer = SerializerFactory.createDefault();
+
+// Serializar mensagem
+Vehicle vehicle = new Vehicle("V123", VehicleType.LIGHT, 10.5, route);
+Message message = new Message(
+    MessageType.VEHICLE_TRANSFER,
+    "Cr1",
+    "Cr2",
+    vehicle
+);
+byte[] data = serializer.serialize(message);
+
+// Enviar via socket
+outputStream.write(data);
+
+// Receber e desserializar
+byte[] received = inputStream.readAllBytes();
+Message msg = serializer.deserialize(received, Message.class);
+Vehicle v = msg.getPayloadAs(Vehicle.class);
+```
+
+---
+
+## Desenvolvimento
+
+### Estado do Projeto
+
+| Componente | Estado | Notas |
+|------------|--------|-------|
+| Modelo de Dados | Completo | Vehicle, Message, Event, etc. |
+| Simulação DES | Completo | Single-process funcional |
+| Serialização | Completo | JSON e Java implementados |
+| Testes | 14/14 | Suite de serialização |
+| Processos Distribuídos | Planeado | Próxima etapa |
+| Comunicação Sockets | Planeado | Em design |
+| Dashboard | Planeado | UI web |
+
+### Roteiro de Desenvolvimento
+
+#### Fase 1: Fundações (Concluído)
+- Modelação de classes
+- Simulação DES single-process
+- Design de protocolo de serialização
+- Implementação JSON/Java serialization
+- Testes unitários
+
+#### Fase 2: Distribuição (Em Curso)
+- Implementar comunicação via sockets
+- Separar cruzamentos em processos
+- Implementar threads de semáforos
+- Testar comunicação entre processos
+
+#### Fase 3: Dashboard e Monitorização
+- Dashboard server
+- UI web em tempo real
+- Visualização de estatísticas
+- Logs estruturados
+
+#### Fase 4: Optimização e Análise
+- Testes de carga
+- Análise de diferentes políticas
+- Recolha de métricas
+- Relatório final
+
+### Executar Testes
+
+```bash
+# Todos os testes
+mvn test
+
+# Apenas testes de serialização
+mvn test -Dtest=SerializationTest
+
+# Com relatório de cobertura
+mvn test jacoco:report
+```
+
+### Contribuir
+
+1. Fork o projeto
+2. Criar uma branch para a funcionalidade (`git checkout -b feature/MinhaFuncionalidade`)
+3. Commit das alterações (`git commit -m 'Adiciona MinhaFuncionalidade'`)
+4. Push para a branch (`git push origin feature/MinhaFuncionalidade`)
+5. Abrir um Pull Request
+
+---
+
+## Métricas de Desempenho
+
+### Serialização
+
+| Formato | Tamanho | Latência | Throughput |
+|---------|---------|----------|------------|
+| JSON | 300 bytes | 40.79 μs | ~24k msgs/s |
+| Java | 657 bytes | 33.34 μs | ~30k msgs/s |
+
+**Conclusão**: JSON é 54% menor com overhead desprezível (7 μs)
+
+### Simulação
+
+- **Veículos gerados/s**: ~0.5-1.0 (configurável)
+- **Throughput**: ~0.2 veículos/s (saída)
+- **Tempo de execução**: 140ms para 60s de simulação
+- **Overhead**: < 0.25% do tempo simulado
+
+---
+
+## Protocolo de Mensagens - Resumo
+
+### Formato Base
+
+```
++------------------+
+| Message Header   |
+|------------------|
+| messageId        | UUID único
+| type             | Enum MessageType
+| senderId         | ID do processo remetente
+| destinationId    | ID do processo destino (null = broadcast)
+| timestamp        | Tempo de criação (ms)
++------------------+
+| Payload          |
+|------------------|
+| Object           | Dados específicos do tipo de mensagem
++------------------+
+```
+
+### Serialização
+
+- **Formato**: JSON (UTF-8)
+- **Biblioteca**: Gson 2.10.1
+- **Codificação**: UTF-8
+- **Compressão**: Opcional (gzip)
+
+### Transporte
+
+- **Protocolo**: TCP/IP
+- **Porta base**: 5000+ (configurável)
+- **Timeout**: 30s
+- **Keep-alive**: Heartbeat a cada 5s
+
+---
+
+## Segurança
+
+### Considerações
+
+1. **Validação de Mensagens**
+   - Verificar tipos esperados
+   - Validar intervalos de valores
+   - Rejeitar mensagens malformadas
+
+2. **Autenticação** (Planeado)
+   - Autenticação baseada em token
+   - Whitelist de processos
+
+3. **Encriptação** (Opcional)
+   - TLS/SSL para produção
+   - Não necessário para ambiente de desenvolvimento local
+
+---
+
+## Licença
+
+Este projeto é desenvolvido para fins académicos no âmbito da disciplina de Sistemas Distribuídos (SD) do Instituto Politécnico do Porto.
+
+---
+
+## Equipa
+
+**Instituição**: Instituto Politécnico do Porto  
+**Curso**: Sistemas Distribuídos  
+**Ano Letivo**: 2025-2026 (1º Semestre)
+
+---
+
+## Suporte
+
+Para questões ou problemas:
+
+1. Consultar a [documentação](./main/docs/README.md)
+2. Ver [exemplos de código](./main/src/main/java/sd/serialization/SerializationExample.java)
+3. Executar testes: `mvn test`
+4. Abrir issue no GitHub
+
+---
+
+## Ligações Úteis
+
+- [Documentação do Projeto](./main/docs/README.md)
+- [Plano de Desenvolvimento](./TODO.md)
+- [Especificação de Serialização](./main/docs/SERIALIZATION_SPECIFICATION.md)
+- [Guia de Serialização](./main/src/main/java/sd/serialization/README.md)
+
+---
+
+**Última actualização**: 23 de outubro de 2025  
+**Versão**: 1.0.0  
+**Estado**: Em Desenvolvimento Activo

STEP2_SUMMARY.md

@@ -0,0 +1,134 @@
+# 🏁 Single-Process Prototype — Implementation Summary
+
+**Status:** ✅ Complete
+**Date:** October 22, 2025
+**Branch:** `8-single-process-prototype`
+
+---
+
+## Overview
+
+The single-process prototype implements a **discrete event simulation (DES)** of a 3×3 urban grid with five intersections, realistic vehicle behavior, and fully synchronized traffic lights. Everything runs under one process, laying the groundwork for the distributed architecture in Phase 3.
+
+---
+
+## Core Architecture
+
+### **SimulationEngine**
+
+Drives the DES loop with a priority queue of timestamped events — vehicles, lights, crossings, and periodic stats updates. Handles five intersections (Cr1–Cr5) and six event types.
+
+**Main loop:**
+
+```
+while (events && time < duration):
+    event = nextEvent()
+    time = event.timestamp
+    handle(event)
+```
+
+### **VehicleGenerator**
+
+Spawns vehicles via:
+
+* **Poisson arrivals** (λ = 0.5 veh/s) or fixed intervals
+* **Probabilistic routes** from E1–E3
+* **Type distribution**: 20% BIKE, 60% LIGHT, 20% HEAVY
+
+### **StatisticsCollector**
+
+Tracks system-wide and per-type metrics: throughput, avg. wait, queue sizes, light cycles — updated every 10 s and at simulation end.
+
+---
+
+## Model Highlights
+
+* **Vehicle** – type, route, timings, lifecycle.
+* **Intersection** – routing tables, traffic lights, queues.
+* **TrafficLight** – red/green cycles with FIFO queues.
+* **Event** – timestamped, comparable; 6 types for all DES actions.
+
+---
+
+## Configuration (`simulation.properties`)
+
+```properties
+simulation.duration=60.0
+simulation.arrival.model=POISSON
+simulation.arrival.rate=0.5
+
+vehicle.bike.crossingTime=1.5
+vehicle.light.crossingTime=2.0
+vehicle.heavy.crossingTime=4.0
+
+statistics.update.interval=10.0
+```
+
+**Speed logic:**
+`t_bike = 0.5×t_car`, `t_heavy = 2×t_car`.
+
+---
+
+## Topology
+
+```
+E1→Cr1→Cr4→Cr5→S
+E2→Cr2→Cr5→S
+E3→Cr3→S
+Bi-dir: Cr1↔Cr2, Cr2↔Cr3
+```
+
+---
+
+## Results
+
+**Unit Tests:** 7/7 ✅
+**60-Second Simulation:**
+
+* Generated: 22 vehicles
+* Completed: 5 (22.7%)
+* Avg system time: 15.47 s
+* Throughput: 0.08 veh/s
+* All lights & intersections operational
+
+**Performance:**
+~0.03 s real-time run (≈2000× speed-up), < 50 MB RAM.
+
+---
+
+## Code Structure
+
+```
+sd/
+├── engine/SimulationEngine.java
+├── model/{Vehicle,Intersection,TrafficLight,Event}.java
+├── util/{VehicleGenerator,StatisticsCollector}.java
+└── config/SimulationConfig.java
+```
+
+---
+
+## Key Flow
+
+1. Initialize intersections, lights, first events.
+2. Process events chronologically.
+3. Vehicles follow routes → queue → cross → exit.
+4. Lights toggle, queues drain, stats update.
+5. Print summary and performance metrics.
+
+---
+
+## Next Steps — Phase 3
+
+* Split intersections into independent **processes**.
+* Add **socket-based communication**.
+* Run **traffic lights as threads**.
+* Enable **distributed synchronization** and fault handling.
+
+---
+
+## TL;DR
+
+Solid single-process DES ✅
+Everything’s working — traffic lights, routing, vehicles, stats.
+Ready to go distributed next.

TODO.md

@@ -1,3 +1,26 @@
+## ✅ SINGLE-PROCESS PROTOTYPE - COMPLETED
+
+### Phase 2 Status: DONE ✅
+
+All components for the single-process prototype have been successfully implemented and tested:
+
+- ✅ **SimulationEngine** - Priority queue-based discrete event simulation
+- ✅ **VehicleGenerator** - Poisson and Fixed arrival models
+- ✅ **StatisticsCollector** - Comprehensive metrics tracking
+- ✅ **Entry point** - Main simulation runner
+- ✅ **60s test simulation** - Successfully validated event processing and routing
+
+### Test Results:
+- All 7 unit tests passing
+- 60-second simulation completed successfully
+- Generated 22 vehicles with 5 completing their routes
+- Traffic light state changes working correctly
+- Vehicle routing through intersections validated
+
+---
+
+## NEXT: Distributed Architecture Implementation
+
 ### Compreender os Conceitos Fundamentais
 
 Primeiro, as tecnologias e paradigmas chave necessários para este projeto devem ser totalmente compreendidos.
@@ -16,7 +39,7 @@ Primeiro, as tecnologias e paradigmas chave necessários para este projeto devem
         
     - Uma **lista de eventos** central, frequentemente uma fila de prioridades, será necessária para armazenar eventos futuros, ordenados pelo seu timestamp. O ciclo principal da simulação retira o próximo evento da lista, processa-o e adiciona quaisquer novos eventos que resultem dele.
         
-- **Processo de Poisson:** Para o modelo "mais realista" de chegadas de veículos, é especificado um processo de Poisson. A principal conclusão é que o tempo _entre_ chegadas consecutivas de veículos segue uma **distribuição exponencial**. Em Java, este intervalo pode ser gerado usando `Math.log(1 - Math.random()) / -lambda`, onde `lambda` (λi​) é a taxa de chegada especificada.
+- **Processo de Poisson:** Para o modelo 'mais realista' de chegadas de veículos, é especificado um processo de Poisson. A principal conclusão é que o tempo _entre_ chegadas consecutivas de veículos segue uma **distribuição exponencial**. Em Java, este intervalo pode ser gerado usando `Math.log(1 - Math.random()) / -lambda`, onde `lambda` (λi​) é a taxa de chegada especificada.
     
 
 ---
@@ -172,4 +195,4 @@ Assim que o sistema completo estiver a funcionar, as experiências exigidas pela
     
 - **Debugging:** Debugging de sistemas distribuídos podem ser difíceis. Uma framework de logging (como Log4j 2 ou SLF4J) pode ser usada para registar eventos//alterações de estado nos diferentes processos.
     
-- **Configuração:** Valores como endereços IP, números de porta ou parâmetros da simulação não devem ser "hardcoded". Um ficheiro de configuração (ex: um ficheiro `.properties` ou `.json`) torna a aplicação mais fácil de executar e testar.
+- **Configuração:** Valores como endereços IP, números de porta ou parâmetros da simulação não devem ser "hardcoded". Um ficheiro de configuração (ex: um ficheiro `.properties` ou `.json`) torna a aplicação mais fácil de executar e testar.

main/pom.xml

@@ -11,6 +11,79 @@
     <properties>
         <maven.compiler.source>17</maven.compiler.source>
         <maven.compiler.target>17</maven.compiler.target>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     </properties>
 
+    <dependencies>
+        <!-- JUnit 5 for testing -->
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter</artifactId>
+            <version>5.10.0</version>
+            <scope>test</scope>
+        </dependency>
+
+        <!-- Gson for JSON serialization -->
+        <dependency>
+            <groupId>com.google.code.gson</groupId>
+            <artifactId>gson</artifactId>
+            <version>2.10.1</version>
+        </dependency>
+
+        <!-- JavaFX for UI -->
+        <dependency>
+            <groupId>org.openjfx</groupId>
+            <artifactId>javafx-controls</artifactId>
+            <version>17.0.2</version>
+        </dependency>
+        <dependency>
+            <groupId>org.openjfx</groupId>
+            <artifactId>javafx-fxml</artifactId>
+            <version>17.0.2</version>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <!-- Maven Exec Plugin for running examples -->
+            <plugin>
+                <groupId>org.codehaus.mojo</groupId>
+                <artifactId>exec-maven-plugin</artifactId>
+                <version>3.1.0</version>
+                <configuration>
+                    <mainClass>sd.dashboard.Launcher</mainClass>
+                </configuration>
+            </plugin>
+            <!-- JavaFX Maven Plugin -->
+            <plugin>
+                <groupId>org.openjfx</groupId>
+                <artifactId>javafx-maven-plugin</artifactId>
+                <version>0.0.8</version>
+                <configuration>
+                    <mainClass>sd.dashboard.Launcher</mainClass>
+                </configuration>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-shade-plugin</artifactId>
+                <version>3.5.2</version>
+                <executions>
+                    <execution>
+                        <phase>package</phase>
+                        <goals>
+                            <goal>shade</goal>
+                        </goals>
+                        <configuration>
+                            <transformers>
+                                <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
+                                    <mainClass>sd.dashboard.Launcher</mainClass>
+                                </transformer>
+                            </transformers>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+
 </project>

main/src/main/java/sd/Entry.java

@@ -1,7 +0,0 @@
-package sd;
-
-public class Entry {
-    public static void main(String[] args) {
-        System.out.println("Hello, World!");
-    }
-}

main/src/main/java/sd/ExitNodeProcess.java

@@ -0,0 +1,426 @@
+package sd;
+
+import java.io.IOException;
+import java.net.ServerSocket;
+import java.net.Socket;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+
+import sd.config.SimulationConfig;
+import sd.coordinator.SocketClient;
+import sd.dashboard.StatsUpdatePayload;
+import sd.model.Message;
+import sd.model.MessageType;
+import sd.model.Vehicle;
+import sd.model.VehicleType;
+import sd.protocol.MessageProtocol;
+import sd.protocol.SocketConnection;
+
+/**
+ * Processo responsável pelo nó de saída do sistema de simulação de tráfego
+ * distribuído.
+ * 
+ * Este processo representa o ponto final ("S") onde os veículos completam as
+ * suas rotas.
+ * As suas principais responsabilidades são:
+ * - Receber veículos que terminam a sua rota vindos das interseções
+ * - Calcular e agregar estatísticas finais dos veículos
+ * - Enviar estatísticas periódicas para o dashboard
+ * - Gerar relatórios finais ao terminar a simulação
+ */
+public class ExitNodeProcess {
+
+    private final SimulationConfig config;
+    private ServerSocket serverSocket;
+    private final ExecutorService connectionHandlerPool;
+
+    /**
+     * Flag para controlar a execução do processo (volatile para visibilidade entre
+     * threads)
+     */
+    private volatile boolean running;
+
+    /** Simulation start time (milliseconds) to calculate relative times */
+    private long simulationStartMillis;
+
+    /** Counter de veículos que completaram a rota */
+    private int totalVehiclesReceived;
+
+    /** Soma dos tempos no sistema de todos os veículos */
+    private double totalSystemTime;
+
+    /** Soma dos tempos de espera de todos os veículos */
+    private double totalWaitingTime;
+
+    /** Soma dos tempos de travessia de todos os veículos */
+    private double totalCrossingTime;
+
+    /** Contagem de veículos por tipo */
+    private final Map<VehicleType, Integer> vehicleTypeCount;
+
+    /** Tempo total de espera acumulado por tipo de veículo */
+    private final Map<VehicleType, Double> vehicleTypeWaitTime;
+
+    /** Socket para comunicação com o dashboard */
+    private SocketClient dashboardClient;
+
+    /**
+     * Método para iniciar o processo
+     * 
+     * @param args Argumentos da linha de comandos. Se fornecido, args[0] deve ser
+     *             o caminho para um ficheiro de configuração personalizado.
+     */
+    public static void main(String[] args) {
+        System.out.println("=".repeat(60));
+        System.out.println("EXIT NODE PROCESS");
+        System.out.println("=".repeat(60));
+
+        try {
+            String configFile = args.length > 0 ? args[0] : "src/main/resources/simulation.properties";
+            System.out.println("Loading configuration from: " + configFile);
+
+            SimulationConfig config = new SimulationConfig(configFile);
+            ExitNodeProcess exitNode = new ExitNodeProcess(config);
+
+            System.out.println("\n" + "=".repeat(60));
+            exitNode.initialize();
+
+            System.out.println("\n" + "=".repeat(60));
+            exitNode.start();
+
+        } catch (IOException e) {
+            System.err.println("Failed to start exit node: " + e.getMessage());
+            System.exit(1);
+        } catch (Exception e) {
+            System.err.println("Exit node error: " + e.getMessage());
+            System.exit(1);
+        }
+    }
+
+    /**
+     * Constrói um novo processo de nó de saída.
+     * 
+     * Inicializa todas as estruturas de dados necessárias para recolher
+     * estatísticas
+     * e configura o pool de threads para processar as ligações concorrentes.
+     * 
+     * @param config Configuração da simulação contendo portas e endereços dos
+     *               serviços
+     */
+    public ExitNodeProcess(SimulationConfig config) {
+        this.config = config;
+        this.connectionHandlerPool = Executors.newCachedThreadPool();
+        this.running = false;
+
+        this.totalVehiclesReceived = 0;
+        this.totalSystemTime = 0.0;
+        this.totalWaitingTime = 0.0;
+        this.totalCrossingTime = 0.0;
+        this.vehicleTypeCount = new HashMap<>();
+        this.vehicleTypeWaitTime = new HashMap<>();
+
+        // Inicializa os counters para cada tipo de veículo
+        for (VehicleType type : VehicleType.values()) {
+            vehicleTypeCount.put(type, 0);
+            vehicleTypeWaitTime.put(type, 0.0);
+        }
+
+        System.out.println("Exit node initialized");
+        System.out.println("  - Exit port: " + config.getExitPort());
+        System.out.println("  - Dashboard: " + config.getDashboardHost() + ":" + config.getDashboardPort());
+    }
+
+    /**
+     * Inicializa o processo de ligação ao dashboard.
+     * 
+     * Tenta conectar-se ao dashboard. Se a ligação falhar, o processo
+     * continua a funcionar normalmente, mas sem enviar estatísticas.
+     * 
+     */
+    public void initialize() {
+        System.out.println("Connecting to dashboard...");
+
+        try {
+            String host = config.getDashboardHost();
+            int port = config.getDashboardPort();
+
+            dashboardClient = new SocketClient("Dashboard", host, port);
+            dashboardClient.connect();
+
+            System.out.println("Successfully connected to dashboard");
+        } catch (IOException e) {
+            System.err.println("WARNING: Failed to connect to dashboard: " + e.getMessage());
+            System.err.println("Exit node will continue without dashboard connection");
+        }
+    }
+
+    /**
+     * Inicia o socket e começa a aceitar ligações.
+     * 
+     * Este é o loop principal do processo que:
+     * 1. Cria um socket na porta definida
+     * 2. Aguarda pelas ligações das interseções
+     * 3. Delega cada ligação a uma thread da pool para processamento assíncrono
+     * 
+     * @throws IOException Se o socket não puder ser criado ou houver erro na
+     *                     aceitação
+     */
+    public void start() throws IOException {
+        int port = config.getExitPort();
+        serverSocket = new ServerSocket(port);
+        running = true;
+        simulationStartMillis = System.currentTimeMillis();
+
+        System.out.println("Exit node started on port " + port);
+        System.out.println("Waiting for vehicles...\\n");
+
+        while (running) {
+            try {
+                Socket clientSocket = serverSocket.accept();
+                connectionHandlerPool.submit(() -> handleIncomingConnection(clientSocket));
+            } catch (IOException e) {
+                if (running) {
+                    System.err.println("Error accepting connection: " + e.getMessage());
+                }
+            }
+        }
+    }
+
+    /**
+     * Processa uma ligação recebida de uma interseção.
+     * 
+     * Mantém a ligação aberta e processa continuamente mensagens do tipo
+     * VEHICLE_TRANSFER. Cada mensagem representa um veículo que chegou ao nó de
+     * saída.
+     * 
+     * @param clientSocket Socket da ligação estabelecida com a interseção
+     */
+    private void handleIncomingConnection(Socket clientSocket) {
+        String clientAddress = clientSocket.getInetAddress().getHostAddress();
+        System.out.println("New connection accepted from " + clientAddress);
+
+        try (SocketConnection connection = new SocketConnection(clientSocket)) {
+
+            while (running && connection.isConnected()) {
+                try {
+                    System.out.println("[Exit] Waiting for message from " + clientAddress);
+                    MessageProtocol message = connection.receiveMessage();
+                    System.out.println("[Exit] Received message type: " + message.getType() +
+                            " from " + message.getSourceNode());
+
+                    if (message.getType() == MessageType.SIMULATION_START) {
+                        // Coordinator sends start time - use it instead of our local start
+                        simulationStartMillis = ((Number) message.getPayload()).longValue();
+                        System.out.println("[Exit] Simulation start time synchronized");
+                    } else if (message.getType() == MessageType.VEHICLE_TRANSFER) {
+                        Object payload = message.getPayload();
+                        System.out.println("[Exit] Payload type: " + payload.getClass().getName());
+
+                        // Handle Gson LinkedHashMap
+                        Vehicle vehicle;
+                        if (payload instanceof com.google.gson.internal.LinkedTreeMap ||
+                                payload instanceof java.util.LinkedHashMap) {
+                            String json = new com.google.gson.Gson().toJson(payload);
+                            vehicle = new com.google.gson.Gson().fromJson(json, Vehicle.class);
+                        } else {
+                            vehicle = (Vehicle) payload;
+                        }
+
+                        processExitingVehicle(vehicle);
+                    }
+
+                } catch (ClassNotFoundException e) {
+                    System.err.println("[Exit] Unknown message type: " + e.getMessage());
+                    e.printStackTrace();
+                } catch (Exception e) {
+                    System.err.println("[Exit] Error processing message: " + e.getMessage());
+                    e.printStackTrace();
+                }
+            }
+
+            System.out.println("[Exit] Connection closed from " + clientAddress);
+
+        } catch (IOException e) {
+            if (running) {
+                System.err.println("[Exit] Connection error from " + clientAddress + ": " + e.getMessage());
+                e.printStackTrace();
+            }
+        }
+    }
+
+    /**
+     * Processa um veículo que chegou ao nó de saída.
+     * 
+     * Método sincronizado para garantir thread-safety ao atualizar as estatísticas.
+     * Calcula as métricas finais do veículo e atualiza:
+     * - Counters globais;
+     * - Estatísticas por tipo de veículo;
+     * - Faz update ao dashboard a cada 10 veículos.
+     * 
+     * @param vehicle Veículo que completou a sua rota
+     */
+    private synchronized void processExitingVehicle(Vehicle vehicle) {
+        totalVehiclesReceived++;
+
+        // Calculate relative simulation time (seconds since simulation start)
+        double currentSimTime = (System.currentTimeMillis() - simulationStartMillis) / 1000.0;
+        // System time = time vehicle spent in system (current time - entry time)
+        double systemTime = currentSimTime - vehicle.getEntryTime();
+        double waitTime = vehicle.getTotalWaitingTime();
+        double crossingTime = vehicle.getTotalCrossingTime();
+
+        // Store times in seconds, will be converted to ms when sending to dashboard
+        totalSystemTime += systemTime;
+        totalWaitingTime += waitTime;
+        totalCrossingTime += crossingTime;
+
+        VehicleType type = vehicle.getType();
+        vehicleTypeCount.put(type, vehicleTypeCount.get(type) + 1);
+        vehicleTypeWaitTime.put(type, vehicleTypeWaitTime.get(type) + waitTime);
+
+        System.out.printf("[Exit] Vehicle %s completed (type=%s, system_time=%.2fs, wait=%.2fs, crossing=%.2fs)%n",
+                vehicle.getId(), vehicle.getType(), systemTime, waitTime, crossingTime);
+
+        // Send stats after every vehicle to ensure dashboard updates quickly
+        sendStatsToDashboard();
+    }
+
+    /**
+     * Envia as estatísticas para o dashboard.
+     * 
+     * Prepara e envia uma mensagem STATS_UPDATE com:
+     * - O total de veículos processados;
+     * - A média dos tempos (sistema, espera, travessia);
+     * - As contagens e médias por cada tipo de veículo.
+     * 
+     */
+    private void sendStatsToDashboard() {
+        if (dashboardClient == null || !dashboardClient.isConnected()) {
+            return;
+        }
+
+        try {
+            // Create stats payload
+            StatsUpdatePayload payload = new StatsUpdatePayload();
+
+            // Set global stats - convert seconds to milliseconds
+            payload.setTotalVehiclesCompleted(totalVehiclesReceived);
+            payload.setTotalSystemTime((long) (totalSystemTime * 1000.0)); // s -> ms
+            payload.setTotalWaitingTime((long) (totalWaitingTime * 1000.0)); // s -> ms
+
+            // Set intersection-like stats so it shows up correctly in the dashboard table
+            payload.setIntersectionArrivals(totalVehiclesReceived);
+            payload.setIntersectionDepartures(totalVehiclesReceived);
+            payload.setIntersectionQueueSize(0);
+
+            // Set vehicle type stats
+            Map<VehicleType, Integer> typeCounts = new HashMap<>();
+            Map<VehicleType, Long> typeWaitTimes = new HashMap<>();
+
+            for (VehicleType type : VehicleType.values()) {
+                typeCounts.put(type, vehicleTypeCount.get(type));
+                typeWaitTimes.put(type, (long) (vehicleTypeWaitTime.get(type) * 1000.0)); // s -> ms
+            }
+
+            payload.setVehicleTypeCounts(typeCounts);
+            payload.setVehicleTypeWaitTimes(typeWaitTimes);
+
+            // Send message
+            Message message = new Message(
+                    MessageType.STATS_UPDATE,
+                    "ExitNode",
+                    "Dashboard",
+                    payload);
+
+            dashboardClient.send(message);
+
+            double avgWait = totalVehiclesReceived > 0 ? totalWaitingTime / totalVehiclesReceived : 0.0;
+            System.out.printf("[Exit] Sent stats to dashboard (total=%d, avg_wait=%.2fs)%n",
+                    totalVehiclesReceived, avgWait);
+
+        } catch (Exception e) {
+            System.err.println("[Exit] Failed to send stats to dashboard: " + e.getMessage());
+        }
+    }
+
+    /**
+     * Termina o processo
+     * 
+     * Executa a seguinte sequência:
+     * Imprime as estatísticas finais no terminal;
+     * Envia a última atualização de estatísticas ao dashboard;
+     * Fecha o socket;
+     * Aguarda pela finalização das threads;
+     * Fecha a ligação com o dashboard;
+     */
+    public void shutdown() {
+        System.out.println("\n[Exit] Shutting down...");
+        running = false;
+
+        printFinalStatistics();
+
+        sendStatsToDashboard();
+
+        try {
+            if (serverSocket != null && !serverSocket.isClosed()) {
+                serverSocket.close();
+            }
+        } catch (IOException e) {
+            System.err.println("Error closing server socket: " + e.getMessage());
+        }
+
+        connectionHandlerPool.shutdown();
+        try {
+            if (!connectionHandlerPool.awaitTermination(5, TimeUnit.SECONDS)) {
+                connectionHandlerPool.shutdownNow();
+            }
+        } catch (InterruptedException e) {
+            connectionHandlerPool.shutdownNow();
+        }
+
+        if (dashboardClient != null) {
+            dashboardClient.close();
+        }
+
+        System.out.println("[Exit] Shutdown complete.");
+        System.out.println("=".repeat(60));
+    }
+
+    /**
+     * Imprime as estatísticas finais detalhadas no terminal
+     * 
+     * Gera um relatório com:
+     * Total de veículos que completaram a rota;
+     * Médias de tempo no sistema, espera e travessia;
+     * Distribuição e médias pelo tipo de veículo (BIKE, LIGHT, HEAVY);
+     * 
+     * Este método é chamado durante o shutdown para fornecer um resumo
+     * da simulação antes de terminar o processo.
+     */
+    private void printFinalStatistics() {
+        System.out.println("\n=== EXIT NODE STATISTICS ===");
+        System.out.printf("Total Vehicles Completed: %d%n", totalVehiclesReceived);
+
+        if (totalVehiclesReceived > 0) {
+            System.out.printf("%nAVERAGE METRICS:%n");
+            System.out.printf("  System Time: %.2f seconds%n", totalSystemTime / totalVehiclesReceived);
+            System.out.printf("  Waiting Time: %.2f seconds%n", totalWaitingTime / totalVehiclesReceived);
+            System.out.printf("  Crossing Time: %.2f seconds%n", totalCrossingTime / totalVehiclesReceived);
+        }
+
+        System.out.println("\nVEHICLE TYPE DISTRIBUTION:");
+        for (VehicleType type : VehicleType.values()) {
+            int count = vehicleTypeCount.get(type);
+            if (count > 0) {
+                double percentage = (count * 100.0) / totalVehiclesReceived;
+                double avgWait = vehicleTypeWaitTime.get(type) / count;
+                System.out.printf("  %s: %d (%.1f%%), Avg Wait: %.2fs%n",
+                        type, count, percentage, avgWait);
+            }
+        }
+    }
+
+}

main/src/main/java/sd/IntersectionProcess.java

@@ -0,0 +1,664 @@
+package sd;
+
+import java.io.IOException;
+import java.net.ServerSocket;
+import java.net.Socket;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
+
+import sd.config.SimulationConfig;
+import sd.coordinator.SocketClient;
+import sd.dashboard.StatsUpdatePayload;
+import sd.engine.TrafficLightThread;
+import sd.model.Intersection;
+import sd.model.Message;
+import sd.model.MessageType;
+import sd.model.TrafficLight;
+import sd.model.Vehicle;
+import sd.protocol.MessageProtocol;
+import sd.protocol.SocketConnection;
+import sd.serialization.SerializationException;
+
+/**
+ * Main class for an Intersection Process in the distributed traffic simulation.
+ * * Each IntersectionProcess runs as an independent Java application (JVM
+ * instance)
+ * representing one of the five intersections (Cr1-Cr5) in the network.
+ */
+public class IntersectionProcess {
+
+    private final String intersectionId;
+
+    private final SimulationConfig config;
+
+    private final Intersection intersection;
+
+    private ServerSocket serverSocket;
+
+    private final Map<String, SocketConnection> outgoingConnections;
+
+    private final ExecutorService connectionHandlerPool;
+
+    private final ExecutorService trafficLightPool;
+
+    private ScheduledExecutorService statsExecutor;
+    private ScheduledExecutorService departureExecutor;
+
+    private volatile boolean running; // Quando uma thread escreve um valor volatile, todas as outras
+                                      // threads veem a mudança imediatamente.
+
+    // Traffic Light Coordination
+    /**
+     * Lock to ensure mutual exclusion between traffic lights.
+     * Only one traffic light can be green at any given time within this
+     * intersection.
+     */
+    private final Lock trafficCoordinationLock;
+
+    /**
+     * Tracks which direction currently has the green light.
+     * null means no direction is currently green (all are red).
+     */
+    private volatile String currentGreenDirection;
+
+    private SocketClient dashboardClient;
+    private volatile int totalArrivals = 0;
+    private volatile int totalDepartures = 0;
+
+    /**
+     * Constructs a new IntersectionProcess.
+     *
+     * @param intersectionId The ID of this intersection (e.g., "Cr1").
+     * @param configFilePath Path to the simulation.properties file.
+     * @throws IOException If configuration cannot be loaded.
+     */
+    public IntersectionProcess(String intersectionId, String configFilePath) throws IOException {
+        this.intersectionId = intersectionId;
+        this.config = new SimulationConfig(configFilePath);
+        this.intersection = new Intersection(intersectionId);
+        this.outgoingConnections = new HashMap<>();
+        this.connectionHandlerPool = Executors.newCachedThreadPool();
+        this.trafficLightPool = Executors.newFixedThreadPool(4); // Max 4 directions
+        this.statsExecutor = Executors.newSingleThreadScheduledExecutor();
+        this.departureExecutor = Executors.newScheduledThreadPool(4);
+        this.running = false;
+        this.trafficCoordinationLock = new ReentrantLock(true); // Fair lock to prevent starvation
+        this.currentGreenDirection = null;
+
+        System.out.println("=".repeat(60));
+        System.out.println("INTERSECTION PROCESS: " + intersectionId);
+        System.out.println("=".repeat(60));
+    }
+
+    // Main entry point for running an intersection process
+    public static void main(String[] args) {
+        if (args.length < 1) {
+            System.err.println("Usage: java IntersectionProcess <intersectionId> [configFile]");
+            System.err.println("Example: java IntersectionProcess Cr1");
+            System.exit(1);
+        }
+
+        String intersectionId = args[0];
+        String configFile = args.length > 1 ? args[1] : "src/main/resources/simulation.properties";
+
+        try {
+            IntersectionProcess process = new IntersectionProcess(intersectionId, configFile);
+            process.initialize();
+            process.start();
+
+            // Add shutdown hook
+            Runtime.getRuntime().addShutdownHook(new Thread(() -> {
+                System.out.println("\nShutdown signal received...");
+                process.shutdown();
+            }));
+
+        } catch (IOException e) {
+            System.err.println("Failed to start intersection process: " + e.getMessage());
+            e.printStackTrace();
+            System.exit(1);
+        }
+    }
+
+    public void initialize() {
+        System.out.println("\n[" + intersectionId + "] Initializing intersection...");
+
+        createTrafficLights();
+
+        configureRouting();
+
+        connectToDashboard();
+
+        System.out.println("[" + intersectionId + "] Initialization complete.");
+    }
+
+    /**
+     * Establishes connection to the dashboard server for statistics reporting.
+     */
+    private void connectToDashboard() {
+        try {
+            String dashboardHost = config.getDashboardHost();
+            int dashboardPort = config.getDashboardPort();
+
+            System.out.println("[" + intersectionId + "] Connecting to dashboard at " +
+                    dashboardHost + ":" + dashboardPort + "...");
+
+            dashboardClient = new SocketClient(intersectionId, dashboardHost, dashboardPort);
+            dashboardClient.connect();
+
+            System.out.println("[" + intersectionId + "] Connected to dashboard.");
+
+        } catch (IOException e) {
+            System.err.println("[" + intersectionId + "] Failed to connect to dashboard: " +
+                    e.getMessage());
+            System.err.println("[" + intersectionId + "] Will continue without dashboard reporting.");
+            dashboardClient = null;
+        }
+    }
+
+    /**
+     * Creates traffic lights for this intersection based on its physical
+     * connections.
+     * Each intersection has different number and directions of traffic lights
+     * according to the network topology.
+     */
+    private void createTrafficLights() {
+        System.out.println("\n[" + intersectionId + "] Creating traffic lights...");
+
+        SimulationConfig.IntersectionConfig intersectionConfig = getIntersectionConfig();
+        List<String> directions = intersectionConfig.getLights();
+
+        if (directions == null || directions.isEmpty()) {
+            System.err.println("  Warning: No traffic lights configured for " + intersectionId);
+            return;
+        }
+
+        for (String direction : directions) {
+            double greenTime = config.getTrafficLightGreenTime(intersectionId, direction);
+            double redTime = config.getTrafficLightRedTime(intersectionId, direction);
+
+            TrafficLight light = new TrafficLight(
+                    intersectionId + "-" + direction,
+                    direction,
+                    greenTime,
+                    redTime);
+
+            intersection.addTrafficLight(light);
+            System.out.println("  Created traffic light: " + direction +
+                    " (Green: " + greenTime + "s, Red: " + redTime + "s)");
+        }
+    }
+
+    private SimulationConfig.IntersectionConfig getIntersectionConfig() {
+        if (config.getNetworkConfig() == null || config.getNetworkConfig().getIntersections() == null) {
+            throw new RuntimeException("Network configuration not loaded or empty.");
+        }
+        return config.getNetworkConfig().getIntersections().stream()
+                .filter(i -> i.getId().equals(intersectionId))
+                .findFirst()
+                .orElseThrow(() -> new RuntimeException("Intersection config not found for " + intersectionId));
+    }
+
+    private void configureRouting() {
+        System.out.println("\n[" + intersectionId + "] Configuring routing...");
+
+        SimulationConfig.IntersectionConfig intersectionConfig = getIntersectionConfig();
+        Map<String, String> routes = intersectionConfig.getRoutes();
+
+        if (routes != null) {
+            for (Map.Entry<String, String> entry : routes.entrySet()) {
+                String destination = entry.getKey();
+                String direction = entry.getValue();
+                intersection.configureRoute(destination, direction);
+                System.out.println("  Route configured: To " + destination + " -> Use " + direction);
+            }
+        } else {
+            System.out.println("  No routes configured.");
+        }
+
+        System.out.println("  Routing configured.");
+    }
+
+    /**
+     * Requests permission for a traffic light to turn green.
+     * Blocks until permission is granted (no other light is green).
+     * 
+     * @param direction The direction requesting green light
+     */
+    public void requestGreenLight(String direction) {
+        trafficCoordinationLock.lock();
+        currentGreenDirection = direction;
+    }
+
+    /**
+     * Releases the green light permission, allowing another light to turn green.
+     * 
+     * @param direction The direction releasing green light
+     */
+    public void releaseGreenLight(String direction) {
+        if (direction.equals(currentGreenDirection)) {
+            currentGreenDirection = null;
+            trafficCoordinationLock.unlock();
+        }
+    }
+
+    /**
+     * Starts all traffic light threads.
+     */
+    private void startTrafficLights() {
+        System.out.println("\n[" + intersectionId + "] Starting traffic light threads...");
+
+        for (TrafficLight light : intersection.getTrafficLights()) {
+
+            TrafficLightThread lightTask = new TrafficLightThread(light, this, config);
+
+            trafficLightPool.submit(lightTask);
+
+            System.out.println("  Started thread for: " + light.getDirection());
+        }
+    }
+
+    /**
+     * Sends a vehicle to its next destination via socket connection.
+     *
+     * @param vehicle The vehicle that has crossed this intersection.
+     */
+    public void sendVehicleToNextDestination(Vehicle vehicle) {
+        String nextDestination = vehicle.getCurrentDestination();
+
+        // Calculate travel time
+        double baseTime = config.getBaseTravelTime();
+        double multiplier = 1.0;
+        switch (vehicle.getType()) {
+            case BIKE -> multiplier = config.getBikeTravelTimeMultiplier();
+            case HEAVY -> multiplier = config.getHeavyTravelTimeMultiplier();
+            default -> multiplier = 1.0;
+        }
+        double travelTime = baseTime * multiplier;
+        long travelTimeMs = (long) (travelTime * 1000);
+
+        System.out.printf("[%s] Vehicle %s departing to %s. Travel time: %.2fs%n",
+                intersectionId, vehicle.getId(), nextDestination, travelTime);
+
+        // Record departure immediately as it leaves the intersection
+        recordVehicleDeparture();
+
+        // Schedule the arrival at the next node
+        departureExecutor.schedule(() -> {
+            try {
+                // Get or create connection to next destination
+                SocketConnection connection = getOrCreateConnection(nextDestination);
+
+                // Create and send message using Message class
+                MessageProtocol message = new Message(
+                        MessageType.VEHICLE_TRANSFER,
+                        intersectionId,
+                        nextDestination,
+                        vehicle,
+                        System.currentTimeMillis());
+
+                connection.sendMessage(message);
+
+                System.out.println("[" + intersectionId + "] Vehicle " + vehicle.getId() +
+                        " arrived at " + nextDestination + " (msg sent)");
+
+                // Note: vehicle route is advanced when it arrives at the next intersection
+
+            } catch (IOException | InterruptedException e) {
+                System.err.println("[" + intersectionId + "] Failed to send vehicle " +
+                        vehicle.getId() + " to " + nextDestination + ": " + e.getMessage());
+            }
+        }, travelTimeMs, TimeUnit.MILLISECONDS);
+    }
+
+    /**
+     * Gets an existing connection to a destination or creates a new one.
+     *
+     * @param destinationId The ID of the destination node.
+     * @return The SocketConnection to that destination.
+     * @throws IOException          If connection cannot be established.
+     * @throws InterruptedException If connection attempt is interrupted.
+     */
+    private synchronized SocketConnection getOrCreateConnection(String destinationId)
+            throws IOException, InterruptedException {
+
+        if (!outgoingConnections.containsKey(destinationId)) {
+            String host = getHostForDestination(destinationId);
+            int port = getPortForDestination(destinationId);
+
+            System.out.println("[" + intersectionId + "] Creating connection to " +
+                    destinationId + " at " + host + ":" + port);
+
+            SocketConnection connection = new SocketConnection(host, port);
+            outgoingConnections.put(destinationId, connection);
+        }
+
+        return outgoingConnections.get(destinationId);
+    }
+
+    /**
+     * Gets the host address for a destination node from configuration.
+     *
+     * @param destinationId The destination node ID.
+     * @return The host address.
+     */
+    private String getHostForDestination(String destinationId) {
+        if (destinationId.equals("S")) {
+            return config.getExitHost();
+        } else {
+            return config.getIntersectionHost(destinationId);
+        }
+    }
+
+    /**
+     * Gets the port number for a destination node from configuration.
+     *
+     * @param destinationId The destination node ID.
+     * @return The port number.
+     */
+    private int getPortForDestination(String destinationId) {
+        if (destinationId.equals("S")) {
+            return config.getExitPort();
+        } else {
+            return config.getIntersectionPort(destinationId);
+        }
+    }
+
+    /**
+     * Starts the server socket and begins accepting incoming connections.
+     * This is the main listening loop of the process.
+     *
+     * @throws IOException If the server socket cannot be created.
+     */
+    public void start() throws IOException {
+        int port = config.getIntersectionPort(intersectionId);
+        serverSocket = new ServerSocket(port);
+        running = true;
+
+        System.out.println("\n[" + intersectionId + "] Server started on port " + port);
+
+        // Start traffic light threads when running is true
+        startTrafficLights();
+
+        // Start stats updater
+        statsExecutor.scheduleAtFixedRate(this::sendStatsToDashboard, 1, 1, TimeUnit.SECONDS);
+
+        System.out.println("[" + intersectionId + "] Waiting for incoming connections...\n");
+
+        // Main accept loop
+        while (running) {
+            try {
+                Socket clientSocket = serverSocket.accept();
+
+                System.out.println("[" + intersectionId + "] New connection accepted from " +
+                        clientSocket.getInetAddress().getHostAddress());
+
+                // Check running flag again before handling
+                if (!running) {
+                    clientSocket.close();
+                    break;
+                }
+
+                // **Set timeout before submitting to handler**
+                try {
+                    clientSocket.setSoTimeout(1000);
+                } catch (java.net.SocketException e) {
+                    System.err.println("[" + intersectionId + "] Failed to set timeout: " + e.getMessage());
+                    clientSocket.close();
+                    continue;
+                }
+
+                // Handle each connection in a separate thread
+                connectionHandlerPool.submit(() -> handleIncomingConnection(clientSocket));
+
+            } catch (IOException e) {
+                // Expected when serverSocket.close() is called during shutdown
+                if (!running) {
+                    break; // Normal shutdown
+                }
+                System.err.println("[" + intersectionId + "] Error accepting connection: " +
+                        e.getMessage());
+            }
+        }
+    }
+
+    /**
+     * Handles an incoming connection from another process.
+     * Continuously listens for vehicle transfer messages.
+     *
+     * @param clientSocket The accepted socket connection.
+     */
+    private void handleIncomingConnection(Socket clientSocket) {
+        try {
+            clientSocket.setSoTimeout(1000); // 1 second timeout
+
+        } catch (java.net.SocketException e) {
+            System.err.println("[" + intersectionId + "] Failed to set socket timeout: " + e.getMessage());
+            return;
+        }
+
+        try (SocketConnection connection = new SocketConnection(clientSocket)) {
+
+            System.out.println("[" + intersectionId + "] New connection accepted from " +
+                    clientSocket.getInetAddress().getHostAddress());
+
+            // Continuously receive messages while connection is active
+            while (running && connection.isConnected()) {
+                try {
+                    MessageProtocol message = connection.receiveMessage();
+
+                    // Handle simulation start time synchronization
+                    if (message.getType() == MessageType.SIMULATION_START) {
+                        System.out.println("[" + intersectionId + "] Simulation start time synchronized");
+                        continue;
+                    }
+
+                    // Accept both VEHICLE_TRANSFER and VEHICLE_SPAWN (from coordinator)
+                    if (message.getType() == MessageType.VEHICLE_TRANSFER ||
+                            message.getType() == MessageType.VEHICLE_SPAWN) {
+                        // Cast payload to Vehicle - handle Gson deserialization
+                        Vehicle vehicle;
+                        Object payload = message.getPayload();
+                        if (payload instanceof Vehicle) {
+                            vehicle = (Vehicle) payload;
+                        } else if (payload instanceof java.util.Map) {
+                            // Gson deserialized as LinkedHashMap - re-serialize and deserialize as Vehicle
+                            com.google.gson.Gson gson = new com.google.gson.Gson();
+                            String json = gson.toJson(payload);
+                            vehicle = gson.fromJson(json, Vehicle.class);
+                        } else {
+                            System.err.println("[" + intersectionId + "] Unknown payload type: " + payload.getClass());
+                            continue;
+                        }
+
+                        System.out.println("[" + intersectionId + "] Received vehicle: " +
+                                vehicle.getId() + " from " + message.getSourceNode());
+
+                        // Advance vehicle to next destination in its route
+                        vehicle.advanceRoute();
+
+                        // Add vehicle to appropriate queue
+                        intersection.receiveVehicle(vehicle);
+
+                        // Record arrival for statistics
+                        recordVehicleArrival();
+                    } else if (message.getType() == MessageType.SHUTDOWN) {
+                        System.out.println(
+                                "[" + intersectionId + "] Received SHUTDOWN command from " + message.getSourceNode());
+                        running = false;
+                        // Close this specific connection
+                        break;
+                    }
+
+                } catch (java.net.SocketTimeoutException e) {
+                    // Timeout - check running flag and continue
+                    if (!running) {
+                        break;
+                    }
+                    // Continue waiting for next message
+                } catch (ClassNotFoundException e) {
+                    System.err.println("[" + intersectionId + "] Unknown message type received: " +
+                            e.getMessage());
+                    break; // Invalid message, close connection
+                } catch (IOException e) {
+                    if (running) {
+                        System.err.println("[" + intersectionId + "] Failed to deserialize message: " +
+                                e.getMessage());
+                        e.printStackTrace(); // For debugging - maybe change//remove later
+                    }
+                    break; // Connection error, close connection
+                }
+            }
+
+        } catch (IOException e) {
+            if (running) {
+                System.err.println("[" + intersectionId + "] Connection error: " + e.getMessage());
+            }
+            // Expected during shutdown
+        }
+    }
+
+    /**
+     * Stops the intersection process gracefully.
+     * Shuts down all threads and closes all connections.
+     */
+    public void shutdown() {
+        // Check if already shutdown
+        if (!running) {
+            return; // Already shutdown, do nothing
+        }
+
+        System.out.println("\n[" + intersectionId + "] Shutting down...");
+        running = false;
+
+        // Send final stats before closing connections
+        sendStatsToDashboard();
+
+        // 1. Close ServerSocket first
+        if (serverSocket != null && !serverSocket.isClosed()) {
+            try {
+                serverSocket.close();
+            } catch (IOException e) {
+                // Expected
+            }
+        }
+
+        // 2. Shutdown thread pools with force
+        if (trafficLightPool != null && !trafficLightPool.isShutdown()) {
+            trafficLightPool.shutdownNow();
+        }
+        if (connectionHandlerPool != null && !connectionHandlerPool.isShutdown()) {
+            connectionHandlerPool.shutdownNow();
+        }
+        if (statsExecutor != null && !statsExecutor.isShutdown()) {
+            statsExecutor.shutdownNow();
+        }
+        if (departureExecutor != null && !departureExecutor.isShutdown()) {
+            departureExecutor.shutdownNow();
+        }
+
+        // 3. Wait briefly for termination (don't block forever)
+        try {
+            if (trafficLightPool != null) {
+                trafficLightPool.awaitTermination(1, TimeUnit.SECONDS);
+            }
+            if (connectionHandlerPool != null) {
+                connectionHandlerPool.awaitTermination(1, TimeUnit.SECONDS);
+            }
+            if (statsExecutor != null) {
+                statsExecutor.awaitTermination(1, TimeUnit.SECONDS);
+            }
+            if (departureExecutor != null) {
+                departureExecutor.awaitTermination(1, TimeUnit.SECONDS);
+            }
+        } catch (InterruptedException e) {
+            Thread.currentThread().interrupt();
+        }
+
+        // 4. Close outgoing connections
+        synchronized (outgoingConnections) {
+            for (SocketConnection conn : outgoingConnections.values()) {
+                try {
+                    conn.close();
+                } catch (Exception e) {
+                    // Ignore
+                }
+            }
+            outgoingConnections.clear();
+        }
+
+        // 5. Close dashboard connection
+        if (dashboardClient != null) {
+            dashboardClient.close();
+        }
+
+        System.out.println("[" + intersectionId + "] Shutdown complete.");
+        System.out.println("============================================================\n");
+    }
+
+    /**
+     * Gets the Intersection object managed by this process.
+     * Useful for testing and monitoring.
+     * 
+     * @return The Intersection object.
+     */
+    public Intersection getIntersection() {
+        return intersection;
+    }
+
+    /**
+     * Records that a vehicle has arrived at this intersection.
+     */
+    public void recordVehicleArrival() {
+        totalArrivals++;
+    }
+
+    /**
+     * Records that a vehicle has departed from this intersection.
+     */
+    public void recordVehicleDeparture() {
+        totalDepartures++;
+    }
+
+    /**
+     * Sends current statistics to the dashboard server.
+     */
+    private void sendStatsToDashboard() {
+        if (dashboardClient == null || !dashboardClient.isConnected()) {
+            return;
+        }
+
+        try {
+            // Calculate current queue size
+            int currentQueueSize = intersection.getTrafficLights().stream()
+                    .mapToInt(TrafficLight::getQueueSize)
+                    .sum();
+
+            StatsUpdatePayload payload = new StatsUpdatePayload()
+                    .setIntersectionArrivals(totalArrivals)
+                    .setIntersectionDepartures(totalDepartures)
+                    .setIntersectionQueueSize(currentQueueSize);
+
+            // Send StatsUpdatePayload directly as the message payload
+            sd.model.Message message = new sd.model.Message(
+                    MessageType.STATS_UPDATE,
+                    intersectionId,
+                    "Dashboard",
+                    payload);
+
+            dashboardClient.send(message);
+
+            System.out.printf("[%s] Sent stats to dashboard (arrivals=%d, departures=%d, queue=%d)%n",
+                    intersectionId, totalArrivals, totalDepartures, currentQueueSize);
+
+        } catch (SerializationException | IOException e) {
+            System.err.println("[" + intersectionId + "] Failed to send stats to dashboard: " + e.getMessage());
+        }
+    }
+}

main/src/main/java/sd/config/SimulationConfig.java

@@ -3,111 +3,410 @@ package sd.config;
 import java.io.FileInputStream;
 import java.io.IOException;
 import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.io.Reader;
+import java.nio.charset.StandardCharsets;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
 import java.util.Properties;
 
+import com.google.gson.Gson;
+
 /**
  * Class to load and manage simulation configurations.
- * Configurations are read from a .properties file.
+ * Configurations are read from a .properties file. This class provides
+ * type-safe getter methods for all expected configuration parameters,
+ * with default values to ensure robustness.
  */
 public class SimulationConfig {
-    private final Properties properties;
 
-    public SimulationConfig(String filePath) throws IOException {
-        properties = new Properties();
-        try (InputStream input = new FileInputStream(filePath)) {
-            properties.load(input);
+    /**
+     * Holds all properties loaded from the file.
+     */
+    private final Properties properties;
+    private NetworkConfig networkConfig;
+
+    public static class NetworkConfig {
+        private List<IntersectionConfig> intersections;
+
+        public List<IntersectionConfig> getIntersections() {
+            return intersections;
         }
     }
 
-    // Network configurations
+    public static class IntersectionConfig {
+        private String id;
+        private List<String> lights;
+        private Map<String, String> routes;
+
+        public String getId() {
+            return id;
+        }
+
+        public List<String> getLights() {
+            return lights;
+        }
+
+        public Map<String, String> getRoutes() {
+            return routes;
+        }
+    }
+
+    /**
+     * Constructs a new SimulationConfig object by loading properties
+     * from the specified file path.
+     * 
+     * This constructor attempts to load the configuration file using multiple
+     * strategies:
+     * 1. Direct file system path
+     * 2. Classpath resource (with automatic path normalization)
+     * 3. Classpath resource with leading slash
+     *
+     * @param filePath The path to the .properties file (e.g.,
+     *                 "src/main/resources/simulation.properties").
+     * @throws IOException If the file cannot be found or read from any location.
+     */
+    public SimulationConfig(String filePath) throws IOException {
+        properties = new Properties();
+
+        // List to track all attempted paths for better error reporting
+        List<String> attemptedPaths = new ArrayList<>();
+        IOException fileSystemException = null;
+
+        // Strategy 1: Try to load directly from file system
+        try (InputStream input = new FileInputStream(filePath)) {
+            properties.load(input);
+            loadNetworkConfig();
+            return; // Successfully loaded from file system
+        } catch (IOException e) {
+            fileSystemException = e;
+            attemptedPaths.add("File system: " + filePath);
+        }
+
+        // Strategy 2: Try to load from classpath with path normalization
+        String resourcePath = filePath;
+
+        // Remove common src/main/resources prefixes
+        resourcePath = resourcePath.replace("src/main/resources/", "").replace("src\\main\\resources\\", "");
+
+        // Remove classpath: prefix if provided
+        if (resourcePath.startsWith("classpath:")) {
+            resourcePath = resourcePath.substring("classpath:".length());
+            if (resourcePath.startsWith("/")) {
+                resourcePath = resourcePath.substring(1);
+            }
+        }
+
+        // Try loading from classpath using thread context class loader
+        InputStream resourceStream = Thread.currentThread().getContextClassLoader().getResourceAsStream(resourcePath);
+        attemptedPaths.add("Classpath (context): " + resourcePath);
+
+        if (resourceStream == null) {
+            // Strategy 3: Try with leading slash
+            String slashPath = "/" + resourcePath;
+            resourceStream = SimulationConfig.class.getResourceAsStream(slashPath);
+            attemptedPaths.add("Classpath (class): " + slashPath);
+        }
+
+        if (resourceStream != null) {
+            try (InputStream input = resourceStream) {
+                properties.load(input);
+                loadNetworkConfig();
+                return; // Successfully loaded from classpath
+            } catch (IOException e) {
+                // Failed to read from classpath resource
+                throw new IOException(
+                        String.format("Failed to read properties from classpath resource '%s': %s",
+                                resourcePath, e.getMessage()),
+                        e);
+            }
+        }
+
+        // All strategies failed - provide comprehensive error message
+        StringBuilder errorMsg = new StringBuilder();
+        errorMsg.append("Configuration file '").append(filePath).append("' could not be found.\n");
+        errorMsg.append("Attempted locations:\n");
+        for (String path : attemptedPaths) {
+            errorMsg.append("  - ").append(path).append("\n");
+        }
+
+        if (fileSystemException != null) {
+            errorMsg.append("\nOriginal error: ").append(fileSystemException.getMessage());
+        }
+
+        throw new IOException(errorMsg.toString(), fileSystemException);
+    }
+
+    private void loadNetworkConfig() {
+        try (InputStream is = getClass().getClassLoader().getResourceAsStream("network_config.json")) {
+            if (is == null) {
+                System.err.println("Warning: network_config.json not found in classpath. Using defaults/empty.");
+                return;
+            }
+            try (Reader reader = new InputStreamReader(is, StandardCharsets.UTF_8)) {
+                Gson gson = new Gson();
+                this.networkConfig = gson.fromJson(reader, NetworkConfig.class);
+            }
+        } catch (IOException e) {
+            System.err.println("Failed to load network_config.json: " + e.getMessage());
+            e.printStackTrace();
+        }
+    }
+
+    public NetworkConfig getNetworkConfig() {
+        return networkConfig;
+    }
+
+    // --- Network configurations ---
+
+    /**
+     * Gets the host address for a specific intersection.
+     * 
+     * @param intersectionId The ID of the intersection (e.g., "Cr1").
+     * @return The host (e.g., "localhost").
+     */
     public String getIntersectionHost(String intersectionId) {
         return properties.getProperty("intersection." + intersectionId + ".host", "localhost");
     }
 
+    /**
+     * Gets the port number for a specific intersection.
+     * 
+     * @param intersectionId The ID of the intersection (e.g., "Cr1").
+     * @return The port number.
+     */
     public int getIntersectionPort(String intersectionId) {
         return Integer.parseInt(properties.getProperty("intersection." + intersectionId + ".port", "0"));
     }
 
+    /**
+     * Gets the host address for the dashboard server.
+     * 
+     * @return The dashboard host.
+     */
     public String getDashboardHost() {
         return properties.getProperty("dashboard.host", "localhost");
     }
 
+    /**
+     * Gets the port number for the dashboard server.
+     * 
+     * @return The dashboard port.
+     */
     public int getDashboardPort() {
         return Integer.parseInt(properties.getProperty("dashboard.port", "9000"));
     }
 
+    /**
+     * Gets the host address for the exit node.
+     * 
+     * @return The exit node host.
+     */
     public String getExitHost() {
         return properties.getProperty("exit.host", "localhost");
     }
 
+    /**
+     * Gets the port number for the exit node.
+     * 
+     * @return The exit node port.
+     */
     public int getExitPort() {
         return Integer.parseInt(properties.getProperty("exit.port", "9001"));
     }
 
-    // Simulation configurations
+    // --- Simulation configurations ---
+
+    /**
+     * Gets the total duration of the simulation in virtual seconds.
+     * 
+     * @return The simulation duration.
+     */
     public double getSimulationDuration() {
         return Double.parseDouble(properties.getProperty("simulation.duration", "3600.0"));
     }
 
+    /**
+     * Gets the drain time (in virtual seconds) to allow vehicles to exit after
+     * generation stops.
+     * 
+     * @return The drain time.
+     */
+    public double getDrainTime() {
+        return Double.parseDouble(properties.getProperty("simulation.drain.time", "60.0"));
+    }
+
+    /**
+     * Gets the vehicle arrival model ("POISSON" or "FIXED").
+     * 
+     * @return The arrival model as a string.
+     */
     public String getArrivalModel() {
         return properties.getProperty("simulation.arrival.model", "POISSON");
     }
 
+    /**
+     * Gets the average arrival rate (lambda) for the POISSON model.
+     * This represents the average number of vehicles arriving per second.
+     * 
+     * @return The arrival rate.
+     */
     public double getArrivalRate() {
         return Double.parseDouble(properties.getProperty("simulation.arrival.rate", "0.5"));
     }
 
+    /**
+     * Gets the fixed time interval between vehicle arrivals for the FIXED model.
+     * 
+     * @return The fixed interval in seconds.
+     */
     public double getFixedArrivalInterval() {
         return Double.parseDouble(properties.getProperty("simulation.arrival.fixed.interval", "2.0"));
     }
 
-    // Traffic light configurations
+    // --- Traffic light configurations ---
+
+    /**
+     * Gets the duration of the GREEN light state for a specific traffic light.
+     * 
+     * @param intersectionId The ID of the intersection (e.g., "Cr1").
+     * @param direction      The direction of the light (e.g., "North").
+     * @return The green light time in seconds.
+     */
     public double getTrafficLightGreenTime(String intersectionId, String direction) {
         String key = "trafficlight." + intersectionId + "." + direction + ".green";
         return Double.parseDouble(properties.getProperty(key, "30.0"));
     }
 
+    /**
+     * Gets the duration of the RED light state for a specific traffic light.
+     * 
+     * @param intersectionId The ID of the intersection (e.g., "Cr1").
+     * @param direction      The direction of the light (e.g., "North").
+     * @return The red light time in seconds.
+     */
     public double getTrafficLightRedTime(String intersectionId, String direction) {
         String key = "trafficlight." + intersectionId + "." + direction + ".red";
         return Double.parseDouble(properties.getProperty(key, "30.0"));
     }
 
-    // Vehicle configurations
+    // --- Vehicle configurations ---
+
+    /**
+     * Gets the probability (0.0 to 1.0) that a generated vehicle is of type LIGHT.
+     * 
+     * @return The probability for LIGHT vehicles.
+     */
     public double getLightVehicleProbability() {
         return Double.parseDouble(properties.getProperty("vehicle.probability.light", "0.7"));
     }
 
+    /**
+     * Gets the average time it takes a LIGHT vehicle to cross an intersection.
+     * 
+     * @return The crossing time in seconds.
+     */
     public double getLightVehicleCrossingTime() {
         return Double.parseDouble(properties.getProperty("vehicle.crossing.time.light", "2.0"));
     }
 
+    /**
+     * Gets the probability (0.0 to 1.0) that a generated vehicle is of type BIKE.
+     * 
+     * @return The probability for BIKE vehicles.
+     */
     public double getBikeVehicleProbability() {
         return Double.parseDouble(properties.getProperty("vehicle.probability.bike", "0.0"));
     }
 
+    /**
+     * Gets the average time it takes a BIKE vehicle to cross an intersection.
+     * 
+     * @return The crossing time in seconds.
+     */
     public double getBikeVehicleCrossingTime() {
         return Double.parseDouble(properties.getProperty("vehicle.crossing.time.bike", "1.5"));
     }
 
+    /**
+     * Gets the probability (0.0 to 1.0) that a generated vehicle is of type HEAVY.
+     * 
+     * @return The probability for HEAVY vehicles.
+     */
     public double getHeavyVehicleProbability() {
         return Double.parseDouble(properties.getProperty("vehicle.probability.heavy", "0.0"));
     }
 
+    /**
+     * Gets the average time it takes a HEAVY vehicle to cross an intersection.
+     * 
+     * @return The crossing time in seconds.
+     */
     public double getHeavyVehicleCrossingTime() {
         return Double.parseDouble(properties.getProperty("vehicle.crossing.time.heavy", "4.0"));
     }
 
-    // Statistics
-    public double getStatisticsUpdateInterval() {
-        return Double.parseDouble(properties.getProperty("statistics.update.interval", "10.0"));
+    /**
+     * Gets the base travel time between intersections for light vehicles.
+     * 
+     * @return The base travel time in seconds.
+     */
+    public double getBaseTravelTime() {
+        return Double.parseDouble(properties.getProperty("vehicle.travel.time.base", "8.0"));
     }
 
-    // Generic method to get any property
+    /**
+     * Gets the travel time multiplier for bike vehicles.
+     * Bike travel time = base time × this multiplier.
+     * 
+     * @return The multiplier for bike travel time.
+     */
+    public double getBikeTravelTimeMultiplier() {
+        return Double.parseDouble(properties.getProperty("vehicle.travel.time.bike.multiplier", "0.5"));
+    }
+
+    /**
+     * Gets the travel time multiplier for heavy vehicles.
+     * Heavy vehicle travel time = base time × this multiplier.
+     * 
+     * @return The multiplier for heavy vehicle travel time.
+     */
+    public double getHeavyTravelTimeMultiplier() {
+        return Double.parseDouble(properties.getProperty("vehicle.travel.time.heavy.multiplier", "4.0"));
+    }
+
+    // --- Statistics ---
+
+    /**
+     * Gets the interval (in virtual seconds) between periodic statistics updates.
+     * 
+     * @return The statistics update interval.
+     */
+    public double getStatisticsUpdateInterval() {
+        return Double.parseDouble(properties.getProperty("statistics.update.interval", "1.0"));
+    }
+
+    // --- Generic getters ---
+
+    /**
+     * Generic method to get any property as a string, with a default value.
+     * 
+     * @param key          The property key.
+     * @param defaultValue The value to return if the key is not found.
+     * @return The property value or the default.
+     */
     public String getProperty(String key, String defaultValue) {
         return properties.getProperty(key, defaultValue);
     }
 
+    /**
+     * Generic method to get any property as a string.
+     * 
+     * @param key The property key.
+     * @return The property value, or null if not found.
+     */
     public String getProperty(String key) {
         return properties.getProperty(key);
     }
-}
+}

main/src/main/java/sd/coordinator/CoordinatorProcess.java

@@ -0,0 +1,302 @@
+package sd.coordinator;
+
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.Map;
+
+import sd.config.SimulationConfig;
+import sd.dashboard.StatsUpdatePayload;
+import sd.model.Message;
+import sd.model.MessageType;
+import sd.model.Vehicle;
+import sd.serialization.SerializationException;
+import sd.util.VehicleGenerator;
+
+/**
+ * Coordinator process responsible for:
+ * 1. Vehicle generation (using VehicleGenerator)
+ * 2. Distributing vehicles to intersection processes via sockets
+ * 3. Managing simulation timing and shutdown
+ * 
+ * This is the main entry point for the distributed simulation architecture.
+ */
+public class CoordinatorProcess {
+
+    private final SimulationConfig config;
+    private final VehicleGenerator vehicleGenerator;
+    private final Map<String, SocketClient> intersectionClients;
+    private SocketClient dashboardClient;
+    private double currentTime;
+    private int vehicleCounter;
+    private boolean running;
+    private double nextGenerationTime;
+
+    public static void main(String[] args) {
+        System.out.println("=".repeat(60));
+        System.out.println("COORDINATOR PROCESS - DISTRIBUTED TRAFFIC SIMULATION");
+        System.out.println("=".repeat(60));
+
+        try {
+            // 1. Load configuration
+            String configFile = args.length > 0 ? args[0] : "src/main/resources/simulation.properties";
+            System.out.println("Loading configuration from: " + configFile);
+
+            SimulationConfig config = new SimulationConfig(configFile);
+            CoordinatorProcess coordinator = new CoordinatorProcess(config);
+
+            // 2. Connect to intersection processes
+            System.out.println("\n" + "=".repeat(60));
+            coordinator.initialize();
+
+            // 3. Run the sim
+            System.out.println("\n" + "=".repeat(60));
+            coordinator.run();
+
+        } catch (IOException e) {
+            System.err.println("Failed to load configuration: " + e.getMessage());
+            System.exit(1);
+        } catch (Exception e) {
+            System.err.println("Coordinator error: " + e.getMessage());
+            System.exit(1);
+        }
+    }
+
+    public CoordinatorProcess(SimulationConfig config) {
+        this.config = config;
+        this.vehicleGenerator = new VehicleGenerator(config);
+        this.intersectionClients = new HashMap<>();
+        this.currentTime = 0.0;
+        this.vehicleCounter = 0;
+        this.running = false;
+        this.nextGenerationTime = 0.0;
+
+        System.out.println("Coordinator initialized with configuration:");
+        System.out.println("  - Simulation duration: " + config.getSimulationDuration() + "s");
+        System.out.println("  - Arrival model: " + config.getArrivalModel());
+        System.out.println("  - Arrival rate: " + config.getArrivalRate() + " vehicles/s");
+    }
+
+    public void initialize() {
+        // Connect to dashboard first
+        connectToDashboard();
+
+        System.out.println("Connecting to intersection processes...");
+
+        String[] intersectionIds = { "Cr1", "Cr2", "Cr3", "Cr4", "Cr5" };
+
+        for (String intersectionId : intersectionIds) {
+            try {
+                String host = config.getIntersectionHost(intersectionId);
+                int port = config.getIntersectionPort(intersectionId);
+
+                SocketClient client = new SocketClient(intersectionId, host, port);
+                client.connect();
+                intersectionClients.put(intersectionId, client);
+
+            } catch (IOException e) {
+                System.err.println("Failed to connect to " + intersectionId + ": " + e.getMessage());
+            }
+        }
+
+        System.out.println("Successfully connected to " + intersectionClients.size() + " intersection(s)");
+
+        if (intersectionClients.isEmpty()) {
+            System.err.println("WARNING: No intersections connected. Simulation cannot proceed.");
+        }
+    }
+
+    public void run() {
+        double duration = config.getSimulationDuration();
+        running = true;
+
+        System.out.println("Starting vehicle generation simulation...");
+        System.out.println("Duration: " + duration + " seconds");
+        System.out.println();
+
+        // Send simulation start time to all processes for synchronization
+        sendSimulationStartTime();
+
+        nextGenerationTime = vehicleGenerator.getNextArrivalTime(currentTime);
+        final double TIME_STEP = 0.1;
+
+        double drainTime = config.getDrainTime();
+        double totalDuration = duration + drainTime;
+        boolean draining = false;
+
+        while (running && currentTime < totalDuration) {
+            // Only generate vehicles during the main duration
+            if (currentTime < duration) {
+                if (currentTime >= nextGenerationTime) {
+                    generateAndSendVehicle();
+                    nextGenerationTime = vehicleGenerator.getNextArrivalTime(currentTime);
+                }
+            } else if (!draining) {
+                draining = true;
+                System.out.println("\n[t=" + String.format("%.2f", currentTime)
+                        + "] Generation complete. Entering DRAIN MODE for " + drainTime + "s...");
+            }
+
+            try {
+                Thread.sleep((long) (TIME_STEP * 1000));
+            } catch (InterruptedException e) {
+                Thread.currentThread().interrupt();
+                break;
+            }
+
+            currentTime += TIME_STEP;
+        }
+
+        System.out.println();
+        System.out.println("Simulation complete at t=" + String.format("%.2f", currentTime) + "s");
+        System.out.println("Total vehicles generated: " + vehicleCounter);
+
+        shutdown();
+    }
+
+    private void generateAndSendVehicle() {
+        Vehicle vehicle = vehicleGenerator.generateVehicle("V" + (++vehicleCounter), currentTime);
+
+        System.out.printf("[t=%.2f] Vehicle %s generated (type=%s, route=%s)%n",
+                currentTime, vehicle.getId(), vehicle.getType(), vehicle.getRoute());
+
+        // Send generation count to dashboard
+        sendGenerationStatsToDashboard();
+
+        if (vehicle.getRoute().isEmpty()) {
+            System.err.println("ERROR: Vehicle " + vehicle.getId() + " has empty route!");
+            return;
+        }
+
+        String entryIntersection = vehicle.getRoute().get(0);
+        sendVehicleToIntersection(vehicle, entryIntersection);
+    }
+
+    private void sendVehicleToIntersection(Vehicle vehicle, String intersectionId) {
+        SocketClient client = intersectionClients.get(intersectionId);
+
+        if (client == null || !client.isConnected()) {
+            System.err.println("ERROR: No connection to " + intersectionId + " for vehicle " + vehicle.getId());
+            return;
+        }
+
+        try {
+            Message message = new Message(
+                    MessageType.VEHICLE_SPAWN,
+                    "COORDINATOR",
+                    intersectionId,
+                    vehicle);
+
+            client.send(message);
+            System.out.printf("->Sent to %s%n", intersectionId);
+
+        } catch (SerializationException | IOException e) {
+            System.err.println("ERROR: Failed to send vehicle " + vehicle.getId() + " to " + intersectionId);
+            System.err.println("Reason: " + e.getMessage());
+        }
+    }
+
+    public void shutdown() {
+        System.out.println();
+        System.out.println("=".repeat(60));
+        System.out.println("Shutting down coordinator...");
+
+        for (Map.Entry<String, SocketClient> entry : intersectionClients.entrySet()) {
+            String intersectionId = entry.getKey();
+            SocketClient client = entry.getValue();
+
+            try {
+                if (client.isConnected()) {
+                    Message personalizedShutdown = new Message(
+                            MessageType.SHUTDOWN,
+                            "COORDINATOR",
+                            intersectionId,
+                            "Simulation complete");
+                    client.send(personalizedShutdown);
+                    System.out.println("Sent shutdown message to " + intersectionId);
+                }
+            } catch (SerializationException | IOException e) {
+                System.err.println("Error sending shutdown to " + intersectionId + ": " + e.getMessage());
+            } finally {
+                client.close();
+            }
+        }
+
+        System.out.println("Coordinator shutdown complete");
+        System.out.println("=".repeat(60));
+    }
+
+    public void stop() {
+        System.out.println("\nStop signal received...");
+        running = false;
+    }
+
+    private void connectToDashboard() {
+        try {
+            String host = config.getDashboardHost();
+            int port = config.getDashboardPort();
+
+            System.out.println("Connecting to dashboard at " + host + ":" + port);
+            dashboardClient = new SocketClient("Dashboard", host, port);
+            dashboardClient.connect();
+            System.out.println("Successfully connected to dashboard\n");
+        } catch (IOException e) {
+            System.err.println("WARNING: Failed to connect to dashboard: " + e.getMessage());
+            System.err.println("Coordinator will continue without dashboard connection\n");
+        }
+    }
+
+    private void sendGenerationStatsToDashboard() {
+        if (dashboardClient == null || !dashboardClient.isConnected()) {
+            return;
+        }
+
+        try {
+            // Create stats payload with vehicle generation count
+            StatsUpdatePayload payload = new StatsUpdatePayload();
+            payload.setTotalVehiclesGenerated(vehicleCounter);
+
+            Message message = new Message(
+                    MessageType.STATS_UPDATE,
+                    "COORDINATOR",
+                    "Dashboard",
+                    payload);
+
+            dashboardClient.send(message);
+        } catch (Exception e) { // This is fine - can add IOException if need be
+            // Don't crash if dashboard update fails
+            System.err.println("Failed to send stats to dashboard: " + e.getMessage());
+        }
+    }
+
+    private void sendSimulationStartTime() {
+        long startTimeMillis = System.currentTimeMillis();
+
+        // Send to all intersections
+        for (Map.Entry<String, SocketClient> entry : intersectionClients.entrySet()) {
+            try {
+                Message message = new Message(
+                        MessageType.SIMULATION_START,
+                        "COORDINATOR",
+                        entry.getKey(),
+                        startTimeMillis);
+                entry.getValue().send(message);
+            } catch (Exception e) { // Same thing here
+                System.err.println("Failed to send start time to " + entry.getKey() + ": " + e.getMessage());
+            }
+        }
+
+        // Send to dashboard
+        if (dashboardClient != null && dashboardClient.isConnected()) {
+            try {
+                Message message = new Message(
+                        MessageType.SIMULATION_START,
+                        "COORDINATOR",
+                        "Dashboard",
+                        startTimeMillis);
+                dashboardClient.send(message);
+            } catch (Exception e) { // And here
+                // Don't crash
+            }
+        }
+    }
+}

main/src/main/java/sd/coordinator/SocketClient.java

@@ -0,0 +1,124 @@
+package sd.coordinator;
+
+import java.io.IOException;
+import java.io.OutputStream;
+import java.net.Socket;
+
+import sd.model.Message;
+import sd.serialization.MessageSerializer;
+import sd.serialization.SerializationException;
+import sd.serialization.SerializerFactory;
+
+/**
+ * Socket client for communication with a single intersection process.
+ * 
+ * Handles a persistent TCP connection to one intersection,
+ * providing a simple way to send serialized messages.
+ */
+public class SocketClient {
+    
+    private final String intersectionId;
+    private final String host;
+    private final int port;
+    private Socket socket;
+    private OutputStream outputStream;
+    private MessageSerializer serializer;
+    
+    /**
+     * Creates a new SocketClient for a given intersection.
+     *
+     * @param intersectionId Intersection ID (ex. "Cr1")
+     * @param host Host address (ex. "localhost")
+     * @param port Port number
+     */
+    public SocketClient(String intersectionId, String host, int port) {
+        this.intersectionId = intersectionId;
+        this.host = host;
+        this.port = port;
+        this.serializer = SerializerFactory.createDefault();
+    }
+    
+    /**
+     * Connects to the intersection process via TCP.
+     * 
+     * @throws IOException if the connection cannot be established
+     */
+
+    public void connect() throws IOException {
+        try {
+            socket = new Socket(host, port);
+            outputStream = socket.getOutputStream();
+            System.out.println("Connected to " + intersectionId + " at " + host + ":" + port);
+        } catch (IOException e) {
+            System.err.println("Failed to connect to " + intersectionId + " at " + host + ":" + port);
+            throw e;
+        }
+    }
+    
+    /**
+     * Sends a message to the connected intersection.
+     * The message is serialized and written over the socket.
+     *
+     * @param message The message to send
+     * @throws SerializationException if serialization fails
+     * @throws IOException if the socket write fails
+     */
+    public void send(Message message) throws SerializationException, IOException {
+        if (socket == null || socket.isClosed()) {
+            throw new IOException("Socket is not connected to " + intersectionId);
+        }
+        
+        try {
+            byte[] data = serializer.serialize(message);
+            
+            // Prefix with message length (so receiver knows how much to read)
+            int length = data.length;
+            outputStream.write((length >> 24) & 0xFF);
+            outputStream.write((length >> 16) & 0xFF);
+            outputStream.write((length >> 8) & 0xFF);
+            outputStream.write(length & 0xFF);
+            
+            outputStream.write(data);
+            outputStream.flush();
+            
+        } catch (SerializationException | IOException e) {
+            System.err.println("Error sending message to " + intersectionId + ": " + e.getMessage());
+            throw e;
+        }
+    }
+    
+    /**
+     * Closes the socket connection safely.
+     * Calling it multiple times won’t cause issues.
+     */
+    public void close() {
+        try {
+            if (outputStream != null) {
+                outputStream.close();
+            }
+            if (socket != null && !socket.isClosed()) {
+                socket.close();
+                System.out.println("Closed connection to " + intersectionId);
+            }
+        } catch (IOException e) {
+            System.err.println("Error closing connection to " + intersectionId + ": " + e.getMessage());
+        }
+    }
+    
+    /**
+     * @return true if connected and socket is open, false otherwise
+     */
+    public boolean isConnected() {
+        return socket != null && socket.isConnected() && !socket.isClosed();
+    }
+    
+    public String getIntersectionId() {
+        return intersectionId;
+    }
+    
+    @Override
+    public String toString() {
+        return String.format("SocketClient[intersection=%s, host=%s, port=%d, connected=%s]",
+            intersectionId, host, port, isConnected());
+    }
+}

main/src/main/java/sd/dashboard/DashboardClientHandler.java

@@ -0,0 +1,137 @@
+package sd.dashboard;
+
+import java.io.IOException;
+import java.net.Socket;
+import java.util.Map;
+
+import sd.model.MessageType;
+import sd.protocol.MessageProtocol;
+import sd.protocol.SocketConnection;
+
+/**
+ * Processes statistics messages from a single client connection.
+ * Runs in a separate thread per client.
+ */
+public class DashboardClientHandler implements Runnable {
+    
+    private final Socket clientSocket;
+    private final DashboardStatistics statistics;
+    
+    public DashboardClientHandler(Socket clientSocket, DashboardStatistics statistics) {
+        this.clientSocket = clientSocket;
+        this.statistics = statistics;
+    }
+    
+    @Override
+    public void run() {
+        String clientInfo = clientSocket.getInetAddress().getHostAddress() + ":" + clientSocket.getPort();
+        
+        try (SocketConnection connection = new SocketConnection(clientSocket)) {
+            System.out.println("[Handler] Started handling client: " + clientInfo);
+            
+            while (!Thread.currentThread().isInterrupted()) {
+                try {
+                    MessageProtocol message = connection.receiveMessage();
+                    
+                    if (message == null) {
+                        System.out.println("[Handler] Client disconnected: " + clientInfo);
+                        break;
+                    }
+                    
+                    processMessage(message);
+                    
+                } catch (ClassNotFoundException e) {
+                    System.err.println("[Handler] Unknown message class from " + clientInfo + ": " + e.getMessage());
+                } catch (IOException e) {
+                    System.out.println("[Handler] Connection error with " + clientInfo + ": " + e.getMessage());
+                    break;
+                }
+            }
+            
+        } catch (IOException e) {
+            System.err.println("[Handler] Error initializing connection with " + clientInfo + ": " + e.getMessage());
+        } finally {
+            try {
+                if (!clientSocket.isClosed()) {
+                    clientSocket.close();
+                }
+            } catch (IOException e) {
+                System.err.println("[Handler] Error closing socket for " + clientInfo + ": " + e.getMessage());
+            }
+        }
+    }
+    
+    private void processMessage(MessageProtocol message) {
+        if (message.getType() != MessageType.STATS_UPDATE) {
+            System.out.println("[Handler] Ignoring non-statistics message type: " + message.getType());
+            return;
+        }
+        
+        String senderId = message.getSourceNode();
+        Object payload = message.getPayload();
+        
+        System.out.println("[Handler] Received STATS_UPDATE from: " + senderId);
+        
+        // Handle both direct StatsUpdatePayload and Gson-deserialized Map
+        StatsUpdatePayload stats;
+        if (payload instanceof StatsUpdatePayload) {
+            stats = (StatsUpdatePayload) payload;
+        } else if (payload instanceof java.util.Map) {
+            // Gson deserialized as LinkedHashMap - re-serialize and deserialize properly
+            com.google.gson.Gson gson = new com.google.gson.Gson();
+            String json = gson.toJson(payload);
+            stats = gson.fromJson(json, StatsUpdatePayload.class);
+        } else {
+            System.err.println("[Handler] Unknown payload type: " + 
+                (payload != null ? payload.getClass().getName() : "null"));
+            return;
+        }
+        
+        updateStatistics(senderId, stats);
+    }
+    
+    private void updateStatistics(String senderId, StatsUpdatePayload stats) {
+        if (stats.getTotalVehiclesGenerated() >= 0) {
+            statistics.updateVehiclesGenerated(stats.getTotalVehiclesGenerated());
+        }
+        
+        if (stats.getTotalVehiclesCompleted() >= 0) {
+            statistics.updateVehiclesCompleted(stats.getTotalVehiclesCompleted());
+        }
+        
+        // Exit Node sends cumulative totals, so we SET rather than ADD
+        if (stats.getTotalSystemTime() >= 0) {
+            statistics.setTotalSystemTime(stats.getTotalSystemTime());
+        }
+        
+        if (stats.getTotalWaitingTime() >= 0) {
+            statistics.setTotalWaitingTime(stats.getTotalWaitingTime());
+        }
+        
+        // Process vehicle type statistics (from Exit Node)
+        if (stats.getVehicleTypeCounts() != null && !stats.getVehicleTypeCounts().isEmpty()) {
+            Map<sd.model.VehicleType, Integer> counts = stats.getVehicleTypeCounts();
+            Map<sd.model.VehicleType, Long> waitTimes = stats.getVehicleTypeWaitTimes();
+            
+            for (var entry : counts.entrySet()) {
+                sd.model.VehicleType type = entry.getKey();
+                int count = entry.getValue();
+                long waitTime = (waitTimes != null && waitTimes.containsKey(type)) 
+                    ? waitTimes.get(type) : 0L;
+                statistics.updateVehicleTypeStats(type, count, waitTime);
+            }
+        }
+        
+        // Process intersection statistics (from Intersection processes)
+        if (senderId.startsWith("Cr") || senderId.startsWith("E")) {
+            statistics.updateIntersectionStats(
+                senderId,
+                stats.getIntersectionArrivals(),
+                stats.getIntersectionDepartures(),
+                stats.getIntersectionQueueSize()
+            );
+        }
+        
+        System.out.println("[Handler] Successfully updated statistics from: " + senderId);
+    }
+}

main/src/main/java/sd/dashboard/DashboardServer.java

@@ -0,0 +1,165 @@
+package sd.dashboard;
+
+import java.io.IOException;
+import java.net.ServerSocket;
+import java.net.Socket;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+import sd.config.SimulationConfig;
+
+/**
+ * Aggregates and displays real-time statistics from all simulation processes.
+ * Uses a thread pool to handle concurrent client connections.
+ */
+public class DashboardServer {
+    
+    private final int port;
+    private final DashboardStatistics statistics;
+    private final ExecutorService clientHandlerPool;
+    private final AtomicBoolean running;
+    private ServerSocket serverSocket;
+    
+    public static void main(String[] args) {
+        // Check if GUI mode is requested
+        boolean useGUI = false;
+        String configFile = "src/main/resources/simulation.properties";
+        
+        for (int i = 0; i < args.length; i++) {
+            if (args[i].equals("--gui") || args[i].equals("-g")) {
+                useGUI = true;
+            } else {
+                configFile = args[i];
+            }
+        }
+        
+        if (useGUI) {
+            // Launch JavaFX UI
+            System.out.println("Launching Dashboard with JavaFX GUI...");
+            DashboardUI.main(args);
+        } else {
+            // Traditional terminal mode
+            System.out.println("=".repeat(60));
+            System.out.println("DASHBOARD SERVER - DISTRIBUTED TRAFFIC SIMULATION");
+            System.out.println("=".repeat(60));
+            
+            try {
+                System.out.println("Loading configuration from: " + configFile);
+                
+                SimulationConfig config = new SimulationConfig(configFile);
+                DashboardServer server = new DashboardServer(config);
+                
+                // Start the server
+                System.out.println("\n" + "=".repeat(60));
+                server.start();
+                
+                // Keep running until interrupted
+                Runtime.getRuntime().addShutdownHook(new Thread(() -> {
+                    System.out.println("\n\nShutdown signal received...");
+                    server.stop();
+                }));
+                
+                // Display statistics periodically
+                server.displayLoop();
+                
+            } catch (IOException e) {
+                System.err.println("Failed to start Dashboard Server: " + e.getMessage());
+                System.exit(1);
+            }
+        }
+    }
+    
+    public DashboardServer(SimulationConfig config) {
+        this.port = config.getDashboardPort();
+        this.statistics = new DashboardStatistics();
+        this.clientHandlerPool = Executors.newFixedThreadPool(10);
+        this.running = new AtomicBoolean(false);
+    }
+    
+    public void start() throws IOException {
+        if (running.get()) {
+            System.out.println("Dashboard Server is already running.");
+            return;
+        }
+        
+        serverSocket = new ServerSocket(port);
+        running.set(true);
+        
+        System.out.println("Dashboard Server started on port " + port);
+        System.out.println("Waiting for statistics updates from simulation processes...");
+        System.out.println("=".repeat(60));
+        
+        Thread acceptThread = new Thread(this::acceptConnections, "DashboardServer-Accept");
+        acceptThread.setDaemon(false);
+        acceptThread.start();
+    }
+    
+    private void acceptConnections() {
+        while (running.get()) {
+            try {
+                Socket clientSocket = serverSocket.accept();
+                System.out.println("[Connection] New client connected: " + 
+                    clientSocket.getInetAddress().getHostAddress() + ":" + clientSocket.getPort());
+                
+                clientHandlerPool.execute(new DashboardClientHandler(clientSocket, statistics));
+                
+            } catch (IOException e) {
+                if (running.get()) {
+                    System.err.println("[Error] Failed to accept client connection: " + e.getMessage());
+                }
+            }
+        }
+    }
+    
+    @SuppressWarnings("BusyWait")
+    private void displayLoop() {
+        final long DISPLAY_INTERVAL_MS = 5000;
+        
+        while (running.get()) {
+            try {
+                Thread.sleep(DISPLAY_INTERVAL_MS);
+                displayStatistics();
+            } catch (InterruptedException e) {
+                Thread.currentThread().interrupt();
+                break;
+            }
+        }
+    }
+    
+    public void displayStatistics() {
+        System.out.println("\n" + "=".repeat(60));
+        System.out.println("REAL-TIME SIMULATION STATISTICS");
+        System.out.println("=".repeat(60));
+        statistics.display();
+        System.out.println("=".repeat(60));
+    }
+    
+    public void stop() {
+        if (!running.get()) {
+            return;
+        }
+        
+        System.out.println("\nStopping Dashboard Server...");
+        running.set(false);
+        
+        try {
+            if (serverSocket != null && !serverSocket.isClosed()) {
+                serverSocket.close();
+            }
+        } catch (IOException e) {
+            System.err.println("Error closing server socket: " + e.getMessage());
+        }
+        
+        clientHandlerPool.shutdownNow();
+        System.out.println("Dashboard Server stopped.");
+    }
+    
+    public DashboardStatistics getStatistics() {
+        return statistics;
+    }
+    
+    public boolean isRunning() {
+        return running.get();
+    }
+}

main/src/main/java/sd/dashboard/DashboardStatistics.java

@@ -0,0 +1,224 @@
+package sd.dashboard;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.atomic.AtomicLong;
+
+import sd.model.VehicleType;
+
+/**
+ * Thread-safe storage for aggregated simulation statistics.
+ * Uses atomic types and concurrent collections for lock-free updates.
+ */
+public class DashboardStatistics {
+    
+    private final AtomicInteger totalVehiclesGenerated;
+    private final AtomicInteger totalVehiclesCompleted;
+    private final AtomicLong totalSystemTime;
+    private final AtomicLong totalWaitingTime;
+    
+    private final Map<String, IntersectionStats> intersectionStats;
+    private final Map<VehicleType, AtomicInteger> vehicleTypeCount;
+    private final Map<VehicleType, AtomicLong> vehicleTypeWaitTime;
+    
+    private volatile long lastUpdateTime;
+    
+    public DashboardStatistics() {
+        this.totalVehiclesGenerated = new AtomicInteger(0);
+        this.totalVehiclesCompleted = new AtomicInteger(0);
+        this.totalSystemTime = new AtomicLong(0);
+        this.totalWaitingTime = new AtomicLong(0);
+        
+        this.intersectionStats = new ConcurrentHashMap<>();
+        this.vehicleTypeCount = new ConcurrentHashMap<>();
+        this.vehicleTypeWaitTime = new ConcurrentHashMap<>();
+        
+        for (VehicleType type : VehicleType.values()) {
+            vehicleTypeCount.put(type, new AtomicInteger(0));
+            vehicleTypeWaitTime.put(type, new AtomicLong(0));
+        }
+        
+        this.lastUpdateTime = System.currentTimeMillis();
+    }
+    
+    public void updateVehiclesGenerated(int count) {
+        totalVehiclesGenerated.set(count);
+        updateTimestamp();
+    }
+    
+    public void incrementVehiclesGenerated() {
+        totalVehiclesGenerated.incrementAndGet();
+        updateTimestamp();
+    }
+    
+    public void updateVehiclesCompleted(int count) {
+        totalVehiclesCompleted.set(count);
+        updateTimestamp();
+    }
+    
+    public void incrementVehiclesCompleted() {
+        totalVehiclesCompleted.incrementAndGet();
+        updateTimestamp();
+    }
+    
+    public void addSystemTime(long timeMs) {
+        totalSystemTime.addAndGet(timeMs);
+        updateTimestamp();
+    }
+    
+    public void setTotalSystemTime(long timeMs) {
+        totalSystemTime.set(timeMs);
+        updateTimestamp();
+    }
+    
+    public void addWaitingTime(long timeMs) {
+        totalWaitingTime.addAndGet(timeMs);
+        updateTimestamp();
+    }
+    
+    public void setTotalWaitingTime(long timeMs) {
+        totalWaitingTime.set(timeMs);
+        updateTimestamp();
+    }
+    
+    public void updateVehicleTypeStats(VehicleType type, int count, long waitTimeMs) {
+        vehicleTypeCount.get(type).set(count);
+        vehicleTypeWaitTime.get(type).set(waitTimeMs);
+        updateTimestamp();
+    }
+    
+    public void incrementVehicleType(VehicleType type) {
+        vehicleTypeCount.get(type).incrementAndGet();
+        updateTimestamp();
+    }
+    
+    public void updateIntersectionStats(String intersectionId, int arrivals, 
+                                       int departures, int currentQueueSize) {
+        intersectionStats.compute(intersectionId, (id, stats) -> {
+            if (stats == null) {
+                stats = new IntersectionStats(intersectionId);
+            }
+            stats.updateStats(arrivals, departures, currentQueueSize);
+            return stats;
+        });
+        updateTimestamp();
+    }
+    
+    private void updateTimestamp() {
+        lastUpdateTime = System.currentTimeMillis();
+    }
+    
+    public int getTotalVehiclesGenerated() {
+        return totalVehiclesGenerated.get();
+    }
+    
+    public int getTotalVehiclesCompleted() {
+        return totalVehiclesCompleted.get();
+    }
+    
+    public double getAverageSystemTime() {
+        int completed = totalVehiclesCompleted.get();
+        if (completed == 0) return 0.0;
+        return (double) totalSystemTime.get() / completed;
+    }
+    
+    public double getAverageWaitingTime() {
+        int completed = totalVehiclesCompleted.get();
+        if (completed == 0) return 0.0;
+        return (double) totalWaitingTime.get() / completed;
+    }
+    
+    public int getVehicleTypeCount(VehicleType type) {
+        return vehicleTypeCount.get(type).get();
+    }
+    
+    public double getAverageWaitingTimeByType(VehicleType type) {
+        int count = vehicleTypeCount.get(type).get();
+        if (count == 0) return 0.0;
+        return (double) vehicleTypeWaitTime.get(type).get() / count;
+    }
+    
+    public IntersectionStats getIntersectionStats(String intersectionId) {
+        return intersectionStats.get(intersectionId);
+    }
+    
+    public Map<String, IntersectionStats> getAllIntersectionStats() {
+        return new HashMap<>(intersectionStats);
+    }
+    
+    public long getLastUpdateTime() {
+        return lastUpdateTime;
+    }
+    
+    public void display() {
+        System.out.println("\n--- GLOBAL STATISTICS ---");
+        System.out.printf("Total Vehicles Generated: %d%n", getTotalVehiclesGenerated());
+        System.out.printf("Total Vehicles Completed: %d%n", getTotalVehiclesCompleted());
+        System.out.printf("Vehicles In Transit: %d%n", 
+            getTotalVehiclesGenerated() - getTotalVehiclesCompleted());
+        System.out.printf("Average System Time: %.2f ms%n", getAverageSystemTime());
+        System.out.printf("Average Waiting Time: %.2f ms%n", getAverageWaitingTime());
+        
+        System.out.println("\n--- VEHICLE TYPE STATISTICS ---");
+        for (VehicleType type : VehicleType.values()) {
+            int count = getVehicleTypeCount(type);
+            double avgWait = getAverageWaitingTimeByType(type);
+            System.out.printf("%s: %d vehicles, avg wait: %.2f ms%n", 
+                type, count, avgWait);
+        }
+        
+        System.out.println("\n--- INTERSECTION STATISTICS ---");
+        if (intersectionStats.isEmpty()) {
+            System.out.println("(No data received yet)");
+        } else {
+            for (IntersectionStats stats : intersectionStats.values()) {
+                stats.display();
+            }
+        }
+        
+        System.out.printf("%nLast Update: %tT%n", lastUpdateTime);
+    }
+    
+    public static class IntersectionStats {
+        private final String intersectionId;
+        private final AtomicInteger totalArrivals;
+        private final AtomicInteger totalDepartures;
+        private final AtomicInteger currentQueueSize;
+        
+        public IntersectionStats(String intersectionId) {
+            this.intersectionId = intersectionId;
+            this.totalArrivals = new AtomicInteger(0);
+            this.totalDepartures = new AtomicInteger(0);
+            this.currentQueueSize = new AtomicInteger(0);
+        }
+        
+        public void updateStats(int arrivals, int departures, int queueSize) {
+            this.totalArrivals.set(arrivals);
+            this.totalDepartures.set(departures);
+            this.currentQueueSize.set(queueSize);
+        }
+        
+        public String getIntersectionId() {
+            return intersectionId;
+        }
+        
+        public int getTotalArrivals() {
+            return totalArrivals.get();
+        }
+        
+        public int getTotalDepartures() {
+            return totalDepartures.get();
+        }
+        
+        public int getCurrentQueueSize() {
+            return currentQueueSize.get();
+        }
+        
+        public void display() {
+            System.out.printf("%s: Arrivals=%d, Departures=%d, Queue=%d%n",
+                intersectionId, getTotalArrivals(), getTotalDepartures(), getCurrentQueueSize());
+        }
+    }
+}

main/src/main/java/sd/dashboard/DashboardUI.java

@@ -0,0 +1,450 @@
+package sd.dashboard;
+
+import java.io.IOException;
+import java.util.Map;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
+
+import javafx.application.Application;
+import javafx.application.Platform;
+import javafx.geometry.Insets;
+import javafx.geometry.Pos;
+import javafx.scene.Scene;
+import javafx.scene.control.Alert;
+import javafx.scene.control.Button;
+import javafx.scene.control.Label;
+import javafx.scene.control.TableColumn;
+import javafx.scene.control.TableView;
+import javafx.scene.control.cell.PropertyValueFactory;
+import javafx.scene.layout.BorderPane;
+import javafx.scene.layout.GridPane;
+import javafx.scene.layout.HBox;
+import javafx.scene.layout.Priority;
+import javafx.scene.layout.Region;
+import javafx.scene.layout.VBox;
+import javafx.scene.shape.Circle;
+import javafx.stage.Stage;
+import sd.config.SimulationConfig;
+import sd.model.VehicleType;
+
+/**
+ * JavaFX-based Dashboard UI for displaying real-time simulation statistics.
+ * Provides a graphical interface with auto-updating statistics panels.
+ */
+public class DashboardUI extends Application {
+
+    private DashboardServer server;
+    private DashboardStatistics statistics;
+
+    // Global Statistics Labels
+    private Label lblVehiclesGenerated;
+    private Label lblVehiclesCompleted;
+    private Label lblVehiclesInTransit;
+    private Label lblAvgSystemTime;
+    private Label lblAvgWaitingTime;
+    private Label lblLastUpdate;
+
+    // Vehicle Type Table
+    private TableView<VehicleTypeRow> vehicleTypeTable;
+
+    // Intersection Table
+    private TableView<IntersectionRow> intersectionTable;
+
+    // Update scheduler
+    private ScheduledExecutorService updateScheduler;
+
+    @Override
+    public void start(Stage primaryStage) {
+        try {
+            // Initialize server
+            String configFile = getParameters().getRaw().isEmpty()
+                    ? "src/main/resources/simulation.properties"
+                    : getParameters().getRaw().get(0);
+
+            SimulationConfig config = new SimulationConfig(configFile);
+            server = new DashboardServer(config);
+            statistics = server.getStatistics();
+
+            // Start the dashboard server
+            server.start();
+
+            // Build UI
+            BorderPane root = new BorderPane();
+            root.getStyleClass().add("root");
+
+            // Header
+            VBox header = createHeader();
+            root.setTop(header);
+
+            // Main content
+            VBox mainContent = createMainContent();
+            root.setCenter(mainContent);
+
+            // Footer
+            HBox footer = createFooter();
+            root.setBottom(footer);
+
+            // Create scene
+            Scene scene = new Scene(root, 1200, 850);
+
+            // Load CSS
+            String cssUrl = getClass().getResource("/dashboard.css").toExternalForm();
+            scene.getStylesheets().add(cssUrl);
+
+            primaryStage.setTitle("Traffic Simulation Dashboard - Real-time Statistics");
+            primaryStage.setScene(scene);
+            primaryStage.show();
+
+            // Start periodic updates
+            startPeriodicUpdates();
+
+            // Handle window close
+            primaryStage.setOnCloseRequest(event -> {
+                shutdown();
+            });
+
+        } catch (Exception e) {
+            showErrorAlert("Failed to start Dashboard Server", e.getMessage());
+            e.printStackTrace();
+            Platform.exit();
+        }
+    }
+
+    private VBox createHeader() {
+        VBox header = new VBox(10);
+        header.getStyleClass().add("header");
+        header.setAlignment(Pos.CENTER);
+
+        Label title = new Label("DISTRIBUTED TRAFFIC SIMULATION DASHBOARD");
+        title.getStyleClass().add("header-title");
+
+        Label subtitle = new Label("Real-time Statistics and Monitoring");
+        subtitle.getStyleClass().add("header-subtitle");
+
+        // Control Buttons
+        HBox controls = new HBox(15);
+        controls.setAlignment(Pos.CENTER);
+
+        Button btnStart = new Button("START SIMULATION");
+        btnStart.getStyleClass().add("button-start");
+
+        Button btnStop = new Button("STOP SIMULATION");
+        btnStop.getStyleClass().add("button-stop");
+        btnStop.setDisable(true);
+
+        SimulationProcessManager processManager = new SimulationProcessManager();
+
+        btnStart.setOnAction(e -> {
+            try {
+                processManager.startSimulation();
+                btnStart.setDisable(true);
+                btnStop.setDisable(false);
+            } catch (IOException ex) {
+                showErrorAlert("Start Failed", "Could not start simulation processes: " + ex.getMessage());
+            }
+        });
+
+        btnStop.setOnAction(e -> {
+            processManager.stopSimulation();
+            btnStart.setDisable(false);
+            btnStop.setDisable(true);
+        });
+
+        controls.getChildren().addAll(btnStart, btnStop);
+
+        header.getChildren().addAll(title, subtitle, controls);
+
+        return header;
+    }
+
+    private VBox createMainContent() {
+        VBox mainContent = new VBox(20);
+        mainContent.setPadding(new Insets(20));
+
+        // Global Statistics Panel
+        VBox globalStatsCard = createGlobalStatisticsPanel();
+
+        // Tables Container
+        HBox tablesContainer = new HBox(20);
+        tablesContainer.setAlignment(Pos.TOP_CENTER);
+
+        // Vehicle Type Statistics Panel
+        VBox vehicleTypeCard = createVehicleTypePanel();
+        HBox.setHgrow(vehicleTypeCard, Priority.ALWAYS);
+
+        // Intersection Statistics Panel
+        VBox intersectionCard = createIntersectionPanel();
+        HBox.setHgrow(intersectionCard, Priority.ALWAYS);
+
+        tablesContainer.getChildren().addAll(vehicleTypeCard, intersectionCard);
+
+        mainContent.getChildren().addAll(globalStatsCard, tablesContainer);
+
+        return mainContent;
+    }
+
+    private VBox createGlobalStatisticsPanel() {
+        VBox card = new VBox();
+        card.getStyleClass().add("card");
+
+        // Card Header
+        HBox cardHeader = new HBox();
+        cardHeader.getStyleClass().add("card-header");
+        Label cardTitle = new Label("Global Statistics");
+        cardTitle.getStyleClass().add("card-title");
+        cardHeader.getChildren().add(cardTitle);
+
+        // Card Content
+        GridPane grid = new GridPane();
+        grid.getStyleClass().add("card-content");
+        grid.setHgap(40);
+        grid.setVgap(15);
+        grid.setAlignment(Pos.CENTER);
+
+        // Initialize labels
+        lblVehiclesGenerated = createStatValueLabel("0");
+        lblVehiclesCompleted = createStatValueLabel("0");
+        lblVehiclesInTransit = createStatValueLabel("0");
+        lblAvgSystemTime = createStatValueLabel("0.00 s");
+        lblAvgWaitingTime = createStatValueLabel("0.00 s");
+
+        // Add labels with descriptions
+        addStatRow(grid, 0, 0, "Total Vehicles Generated", lblVehiclesGenerated);
+        addStatRow(grid, 1, 0, "Total Vehicles Completed", lblVehiclesCompleted);
+        addStatRow(grid, 2, 0, "Vehicles In Transit", lblVehiclesInTransit);
+        addStatRow(grid, 0, 1, "Average System Time", lblAvgSystemTime);
+        addStatRow(grid, 1, 1, "Average Waiting Time", lblAvgWaitingTime);
+
+        card.getChildren().addAll(cardHeader, grid);
+        return card;
+    }
+
+    private VBox createVehicleTypePanel() {
+        VBox card = new VBox();
+        card.getStyleClass().add("card");
+
+        // Card Header
+        HBox cardHeader = new HBox();
+        cardHeader.getStyleClass().add("card-header");
+        Label cardTitle = new Label("Vehicle Type Statistics");
+        cardTitle.getStyleClass().add("card-title");
+        cardHeader.getChildren().add(cardTitle);
+
+        // Table
+        vehicleTypeTable = new TableView<>();
+        vehicleTypeTable.setColumnResizePolicy(TableView.CONSTRAINED_RESIZE_POLICY);
+        vehicleTypeTable.setPrefHeight(300);
+
+        TableColumn<VehicleTypeRow, String> typeCol = new TableColumn<>("Vehicle Type");
+        typeCol.setCellValueFactory(new PropertyValueFactory<>("vehicleType"));
+
+        TableColumn<VehicleTypeRow, Integer> countCol = new TableColumn<>("Count");
+        countCol.setCellValueFactory(new PropertyValueFactory<>("count"));
+
+        TableColumn<VehicleTypeRow, String> avgWaitCol = new TableColumn<>("Avg Wait Time");
+        avgWaitCol.setCellValueFactory(new PropertyValueFactory<>("avgWaitTime"));
+
+        vehicleTypeTable.getColumns().addAll(typeCol, countCol, avgWaitCol);
+
+        card.getChildren().addAll(cardHeader, vehicleTypeTable);
+        return card;
+    }
+
+    private VBox createIntersectionPanel() {
+        VBox card = new VBox();
+        card.getStyleClass().add("card");
+
+        // Card Header
+        HBox cardHeader = new HBox();
+        cardHeader.getStyleClass().add("card-header");
+        Label cardTitle = new Label("Intersection Statistics");
+        cardTitle.getStyleClass().add("card-title");
+        cardHeader.getChildren().add(cardTitle);
+
+        // Table
+        intersectionTable = new TableView<>();
+        intersectionTable.setColumnResizePolicy(TableView.CONSTRAINED_RESIZE_POLICY);
+        intersectionTable.setPrefHeight(300);
+
+        TableColumn<IntersectionRow, String> idCol = new TableColumn<>("Intersection ID");
+        idCol.setCellValueFactory(new PropertyValueFactory<>("intersectionId"));
+
+        TableColumn<IntersectionRow, Integer> arrivalsCol = new TableColumn<>("Total Arrivals");
+        arrivalsCol.setCellValueFactory(new PropertyValueFactory<>("arrivals"));
+
+        TableColumn<IntersectionRow, Integer> departuresCol = new TableColumn<>("Total Departures");
+        departuresCol.setCellValueFactory(new PropertyValueFactory<>("departures"));
+
+        TableColumn<IntersectionRow, Integer> queueCol = new TableColumn<>("Current Queue");
+        queueCol.setCellValueFactory(new PropertyValueFactory<>("queueSize"));
+
+        intersectionTable.getColumns().addAll(idCol, arrivalsCol, departuresCol, queueCol);
+
+        card.getChildren().addAll(cardHeader, intersectionTable);
+        return card;
+    }
+
+    private HBox createFooter() {
+        HBox footer = new HBox(10);
+        footer.getStyleClass().add("footer");
+        footer.setAlignment(Pos.CENTER_LEFT);
+
+        Label statusLabel = new Label("Status:");
+        statusLabel.getStyleClass().add("footer-text");
+        statusLabel.setStyle("-fx-font-weight: bold;");
+
+        Circle statusIndicator = new Circle(6);
+        statusIndicator.setFill(javafx.scene.paint.Color.LIME);
+
+        Label statusText = new Label("Connected and Receiving Data");
+        statusText.getStyleClass().add("footer-text");
+
+        lblLastUpdate = new Label("Last Update: --:--:--");
+        lblLastUpdate.getStyleClass().add("footer-text");
+
+        Region spacer = new Region();
+        HBox.setHgrow(spacer, Priority.ALWAYS);
+
+        footer.getChildren().addAll(statusLabel, statusIndicator, statusText, spacer, lblLastUpdate);
+
+        return footer;
+    }
+
+    private Label createStatValueLabel(String initialValue) {
+        Label label = new Label(initialValue);
+        label.getStyleClass().add("stat-value");
+        return label;
+    }
+
+    private void addStatRow(GridPane grid, int row, int colGroup, String description, Label valueLabel) {
+        VBox container = new VBox(5);
+        container.setAlignment(Pos.CENTER_LEFT);
+
+        Label descLabel = new Label(description);
+        descLabel.getStyleClass().add("stat-label");
+
+        container.getChildren().addAll(descLabel, valueLabel);
+
+        grid.add(container, colGroup, row);
+    }
+
+    private void startPeriodicUpdates() {
+        updateScheduler = Executors.newSingleThreadScheduledExecutor();
+        updateScheduler.scheduleAtFixedRate(() -> {
+            Platform.runLater(this::updateUI);
+        }, 0, 100, TimeUnit.MILLISECONDS);
+    }
+
+    private void updateUI() {
+        // Update global statistics
+        lblVehiclesGenerated.setText(String.valueOf(statistics.getTotalVehiclesGenerated()));
+        lblVehiclesCompleted.setText(String.valueOf(statistics.getTotalVehiclesCompleted()));
+        lblVehiclesInTransit.setText(String.valueOf(
+                statistics.getTotalVehiclesGenerated() - statistics.getTotalVehiclesCompleted()));
+        lblAvgSystemTime.setText(String.format("%.2f s", statistics.getAverageSystemTime() / 1000.0));
+        lblAvgWaitingTime.setText(String.format("%.2f s", statistics.getAverageWaitingTime() / 1000.0));
+        lblLastUpdate.setText(String.format("Last Update: %tT", statistics.getLastUpdateTime()));
+
+        // Update vehicle type table
+        vehicleTypeTable.getItems().clear();
+        for (VehicleType type : VehicleType.values()) {
+            int count = statistics.getVehicleTypeCount(type);
+            double avgWait = statistics.getAverageWaitingTimeByType(type);
+            vehicleTypeTable.getItems().add(new VehicleTypeRow(
+                    type.toString(), count, String.format("%.2f s", avgWait / 1000.0)));
+        }
+
+        // Update intersection table
+        intersectionTable.getItems().clear();
+        Map<String, DashboardStatistics.IntersectionStats> intersectionStats = statistics.getAllIntersectionStats();
+        for (DashboardStatistics.IntersectionStats stats : intersectionStats.values()) {
+            intersectionTable.getItems().add(new IntersectionRow(
+                    stats.getIntersectionId(),
+                    stats.getTotalArrivals(),
+                    stats.getTotalDepartures(),
+                    stats.getCurrentQueueSize()));
+        }
+    }
+
+    private void shutdown() {
+        System.out.println("Shutting down Dashboard UI...");
+
+        if (updateScheduler != null && !updateScheduler.isShutdown()) {
+            updateScheduler.shutdownNow();
+        }
+
+        if (server != null) {
+            server.stop();
+        }
+
+        Platform.exit();
+    }
+
+    private void showErrorAlert(String title, String message) {
+        Alert alert = new Alert(Alert.AlertType.ERROR);
+        alert.setTitle(title);
+        alert.setHeaderText(null);
+        alert.setContentText(message);
+        alert.showAndWait();
+    }
+
+    public static void main(String[] args) {
+        launch(args);
+    }
+
+    // Inner classes for TableView data models
+    public static class VehicleTypeRow {
+        private final String vehicleType;
+        private final int count;
+        private final String avgWaitTime;
+
+        public VehicleTypeRow(String vehicleType, int count, String avgWaitTime) {
+            this.vehicleType = vehicleType;
+            this.count = count;
+            this.avgWaitTime = avgWaitTime;
+        }
+
+        public String getVehicleType() {
+            return vehicleType;
+        }
+
+        public int getCount() {
+            return count;
+        }
+
+        public String getAvgWaitTime() {
+            return avgWaitTime;
+        }
+    }
+
+    public static class IntersectionRow {
+        private final String intersectionId;
+        private final int arrivals;
+        private final int departures;
+        private final int queueSize;
+
+        public IntersectionRow(String intersectionId, int arrivals, int departures, int queueSize) {
+            this.intersectionId = intersectionId;
+            this.arrivals = arrivals;
+            this.departures = departures;
+            this.queueSize = queueSize;
+        }
+
+        public String getIntersectionId() {
+            return intersectionId;
+        }
+
+        public int getArrivals() {
+            return arrivals;
+        }
+
+        public int getDepartures() {
+            return departures;
+        }
+
+        public int getQueueSize() {
+            return queueSize;
+        }
+    }
+}

main/src/main/java/sd/dashboard/Launcher.java

@@ -0,0 +1,7 @@
+package sd.dashboard;
+
+public class Launcher {
+    public static void main(String[] args) {
+        DashboardUI.main(args);
+    }
+}

main/src/main/java/sd/dashboard/SimulationProcessManager.java

@@ -0,0 +1,118 @@
+package sd.dashboard;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Manages the lifecycle of simulation processes (Intersections, Exit Node,
+ * Coordinator).
+ * Allows starting and stopping the distributed simulation from within the Java
+ * application.
+ */
+public class SimulationProcessManager {
+
+    private final List<Process> runningProcesses;
+    private final String classpath;
+
+    public SimulationProcessManager() {
+        this.runningProcesses = new ArrayList<>();
+        this.classpath = System.getProperty("java.class.path");
+    }
+
+    /**
+     * Starts the full simulation: 5 Intersections, 1 Exit Node, and 1 Coordinator.
+     * 
+     * @throws IOException If a process fails to start.
+     */
+    public void startSimulation() throws IOException {
+        if (!runningProcesses.isEmpty()) {
+            stopSimulation();
+        }
+
+        System.out.println("Starting simulation processes...");
+
+        // 1. Start Intersections (Cr1 - Cr5)
+        String[] intersectionIds = { "Cr1", "Cr2", "Cr3", "Cr4", "Cr5" };
+        for (String id : intersectionIds) {
+            startProcess("sd.IntersectionProcess", id);
+        }
+
+        // 2. Start Exit Node
+        startProcess("sd.ExitNodeProcess", null);
+
+        // 3. Start Coordinator (Wait a bit for others to initialize)
+        try {
+            Thread.sleep(1000);
+        } catch (InterruptedException e) {
+            Thread.currentThread().interrupt();
+        }
+        startProcess("sd.coordinator.CoordinatorProcess", null);
+
+        System.out.println("All simulation processes started.");
+    }
+
+    /**
+     * Stops all running simulation processes.
+     */
+    public void stopSimulation() {
+        System.out.println("Stopping simulation processes...");
+
+        for (Process process : runningProcesses) {
+            if (process.isAlive()) {
+                process.destroy(); // Try graceful termination first
+            }
+        }
+
+        // Wait a bit and force kill if necessary
+        try {
+            Thread.sleep(500);
+        } catch (InterruptedException e) {
+            Thread.currentThread().interrupt();
+        }
+
+        for (Process process : runningProcesses) {
+            if (process.isAlive()) {
+                process.destroyForcibly();
+            }
+        }
+
+        runningProcesses.clear();
+        System.out.println("All simulation processes stopped.");
+    }
+
+    /**
+     * Helper to start a single Java process.
+     */
+    private void startProcess(String className, String arg) throws IOException {
+        String javaBin = System.getProperty("java.home") + File.separator + "bin" + File.separator + "java";
+
+        ProcessBuilder builder;
+        if (arg != null) {
+            builder = new ProcessBuilder(javaBin, "-cp", classpath, className, arg);
+        } else {
+            builder = new ProcessBuilder(javaBin, "-cp", classpath, className);
+        }
+
+        // get the OS temp folder
+        // Linux: /tmp/
+        // Windows: %AppData%\Local\Temp\
+        String tempDir = System.getProperty("java.io.tmpdir");
+
+        String logName = className.substring(className.lastIndexOf('.') + 1) + (arg != null ? "-" + arg : "") + ".log";
+
+        // use the (File parent, String child) constructor to handle slash/backslash
+        // automatically
+        File logFile = new File(tempDir, logName);
+
+        builder.redirectOutput(logFile);
+        builder.redirectError(logFile);
+
+        Process process = builder.start();
+        runningProcesses.add(process);
+        System.out.println("Started " + className + (arg != null ? " " + arg : ""));
+        // print where the logs are actually going
+        System.out.println("Logs redirected to: " + logFile.getAbsolutePath());
+    }
+}

main/src/main/java/sd/dashboard/StatsMessage.java

@@ -0,0 +1,48 @@
+package sd.dashboard;
+
+import sd.model.MessageType;
+import sd.protocol.MessageProtocol;
+
+/**
+ * Message wrapper for sending statistics to the dashboard.
+ */
+public class StatsMessage implements MessageProtocol {
+    
+    private static final long serialVersionUID = 1L;
+    
+    private final String sourceNode;
+    private final String destinationNode;
+    private final StatsUpdatePayload payload;
+    
+    public StatsMessage(String sourceNode, StatsUpdatePayload payload) {
+        this.sourceNode = sourceNode;
+        this.destinationNode = "DashboardServer";
+        this.payload = payload;
+    }
+    
+    @Override
+    public MessageType getType() {
+        return MessageType.STATS_UPDATE;
+    }
+    
+    @Override
+    public Object getPayload() {
+        return payload;
+    }
+    
+    @Override
+    public String getSourceNode() {
+        return sourceNode;
+    }
+    
+    @Override
+    public String getDestinationNode() {
+        return destinationNode;
+    }
+    
+    @Override
+    public String toString() {
+        return String.format("StatsMessage[from=%s, to=%s, payload=%s]", 
+            sourceNode, destinationNode, payload);
+    }
+}

main/src/main/java/sd/dashboard/StatsUpdatePayload.java

@@ -0,0 +1,121 @@
+package sd.dashboard;
+
+import java.io.Serializable;
+import java.util.HashMap;
+import java.util.Map;
+
+import sd.model.VehicleType;
+
+/**
+ * Data transfer object for statistics updates to the dashboard.
+ * Use -1 for fields not being updated in this message.
+ */
+public class StatsUpdatePayload implements Serializable {
+    
+    private static final long serialVersionUID = 1L;
+    
+    private int totalVehiclesGenerated = -1;
+    private int totalVehiclesCompleted = -1;
+    private long totalSystemTime = -1;
+    private long totalWaitingTime = -1;
+    
+    private int intersectionArrivals = 0;
+    private int intersectionDepartures = 0;
+    private int intersectionQueueSize = 0;
+    
+    private Map<VehicleType, Integer> vehicleTypeCounts;
+    private Map<VehicleType, Long> vehicleTypeWaitTimes;
+    
+    public StatsUpdatePayload() {
+        this.vehicleTypeCounts = new HashMap<>();
+        this.vehicleTypeWaitTimes = new HashMap<>();
+    }
+    
+    public int getTotalVehiclesGenerated() {
+        return totalVehiclesGenerated;
+    }
+    
+    public int getTotalVehiclesCompleted() {
+        return totalVehiclesCompleted;
+    }
+    
+    public long getTotalSystemTime() {
+        return totalSystemTime;
+    }
+    
+    public long getTotalWaitingTime() {
+        return totalWaitingTime;
+    }
+    
+    public int getIntersectionArrivals() {
+        return intersectionArrivals;
+    }
+    
+    public int getIntersectionDepartures() {
+        return intersectionDepartures;
+    }
+    
+    public int getIntersectionQueueSize() {
+        return intersectionQueueSize;
+    }
+    
+    public Map<VehicleType, Integer> getVehicleTypeCounts() {
+        return vehicleTypeCounts;
+    }
+    
+    public Map<VehicleType, Long> getVehicleTypeWaitTimes() {
+        return vehicleTypeWaitTimes;
+    }
+    
+    public StatsUpdatePayload setTotalVehiclesGenerated(int totalVehiclesGenerated) {
+        this.totalVehiclesGenerated = totalVehiclesGenerated;
+        return this;
+    }
+    
+    public StatsUpdatePayload setTotalVehiclesCompleted(int totalVehiclesCompleted) {
+        this.totalVehiclesCompleted = totalVehiclesCompleted;
+        return this;
+    }
+    
+    public StatsUpdatePayload setTotalSystemTime(long totalSystemTime) {
+        this.totalSystemTime = totalSystemTime;
+        return this;
+    }
+    
+    public StatsUpdatePayload setTotalWaitingTime(long totalWaitingTime) {
+        this.totalWaitingTime = totalWaitingTime;
+        return this;
+    }
+    
+    public StatsUpdatePayload setIntersectionArrivals(int intersectionArrivals) {
+        this.intersectionArrivals = intersectionArrivals;
+        return this;
+    }
+    
+    public StatsUpdatePayload setIntersectionDepartures(int intersectionDepartures) {
+        this.intersectionDepartures = intersectionDepartures;
+        return this;
+    }
+    
+    public StatsUpdatePayload setIntersectionQueueSize(int intersectionQueueSize) {
+        this.intersectionQueueSize = intersectionQueueSize;
+        return this;
+    }
+    
+    public StatsUpdatePayload setVehicleTypeCounts(Map<VehicleType, Integer> vehicleTypeCounts) {
+        this.vehicleTypeCounts = vehicleTypeCounts;
+        return this;
+    }
+    
+    public StatsUpdatePayload setVehicleTypeWaitTimes(Map<VehicleType, Long> vehicleTypeWaitTimes) {
+        this.vehicleTypeWaitTimes = vehicleTypeWaitTimes;
+        return this;
+    }
+    
+    @Override
+    public String toString() {
+        return String.format("StatsUpdatePayload[generated=%d, completed=%d, arrivals=%d, departures=%d, queueSize=%d]",
+            totalVehiclesGenerated, totalVehiclesCompleted, intersectionArrivals, 
+            intersectionDepartures, intersectionQueueSize);
+    }
+}

main/src/main/java/sd/engine/TrafficLightThread.java

@@ -0,0 +1,126 @@
+package sd.engine;
+
+import sd.IntersectionProcess;
+import sd.config.SimulationConfig;
+import sd.model.TrafficLight;
+import sd.model.TrafficLightState;
+import sd.model.Vehicle;
+
+/**
+ * Implements the control logic for a single TrafficLight
+ * as a Runnable task that runs in its own Thread.
+ */
+public class TrafficLightThread implements Runnable {
+
+    private final TrafficLight light;
+    private final IntersectionProcess process;
+    private final SimulationConfig config;
+    private volatile boolean running;
+
+    // Store the thread reference for proper interruption
+    private Thread currentThread;
+
+    public TrafficLightThread(TrafficLight light, IntersectionProcess process, SimulationConfig config) {
+        this.light = light;
+        this.process = process;
+        this.config = config;
+        this.running = false;
+    }
+
+    @Override
+    public void run() {
+        this.currentThread = Thread.currentThread();
+        this.running = true;
+        System.out.println("[" + light.getId() + "] Traffic light thread started.");
+
+        try {
+            while (running && !Thread.currentThread().isInterrupted()) {
+
+                // Request permission to turn green (blocks until granted)
+                process.requestGreenLight(light.getDirection());
+
+                try {
+                    // --- GREEN Phase ---
+                    light.changeState(TrafficLightState.GREEN);
+                    System.out.println("[" + light.getId() + "] State: GREEN");
+
+                    // Process queue for the duration of the green light
+                    long greenDurationMs = (long) (light.getGreenTime() * 1000);
+                    processGreenLightQueue(greenDurationMs);
+
+                    if (!running || Thread.currentThread().isInterrupted())
+                        break;
+
+                    // --- RED Phase ---
+                    light.changeState(TrafficLightState.RED);
+                    System.out.println("[" + light.getId() + "] State: RED");
+
+                } finally {
+                    // Always release the green light permission
+                    process.releaseGreenLight(light.getDirection());
+                }
+
+                // Wait for red duration
+                Thread.sleep((long) (light.getRedTime() * 1000));
+            }
+        } catch (InterruptedException e) {
+            System.out.println("[" + light.getId() + "] Traffic light thread interrupted.");
+            Thread.currentThread().interrupt();
+        } finally {
+            this.running = false;
+            System.out.println("[" + light.getId() + "] Traffic light thread stopped.");
+        }
+    }
+
+    private void processGreenLightQueue(long greenDurationMs) throws InterruptedException {
+        long startTime = System.currentTimeMillis();
+
+        while (running && !Thread.currentThread().isInterrupted()
+                && light.getState() == TrafficLightState.GREEN) {
+
+            // Check if green time has expired
+            long elapsed = System.currentTimeMillis() - startTime;
+            if (elapsed >= greenDurationMs) {
+                break;
+            }
+
+            if (light.getQueueSize() > 0) {
+                Vehicle vehicle = light.removeVehicle();
+
+                if (vehicle != null) {
+                    double crossingTime = getCrossingTimeForVehicle(vehicle);
+                    long crossingTimeMs = (long) (crossingTime * 1000);
+
+                    Thread.sleep(crossingTimeMs);
+
+                    vehicle.addCrossingTime(crossingTime);
+                    process.getIntersection().incrementVehiclesSent();
+                    process.sendVehicleToNextDestination(vehicle);
+                }
+            } else {
+                // Queue is empty, wait briefly for new vehicles or until time expires
+                Thread.sleep(50);
+            }
+        }
+    }
+
+    private double getCrossingTimeForVehicle(Vehicle vehicle) {
+        return switch (vehicle.getType()) {
+            case BIKE -> config.getBikeVehicleCrossingTime();
+            case LIGHT -> config.getLightVehicleCrossingTime();
+            case HEAVY -> config.getHeavyVehicleCrossingTime();
+            default -> config.getLightVehicleCrossingTime();
+        };
+    }
+
+    /**
+     * Requests the thread to stop gracefully.
+     * Sets the running flag and interrupts the thread to unblock any sleep() calls.
+     */
+    public void shutdown() {
+        this.running = false;
+        if (currentThread != null && currentThread.isAlive()) {
+            currentThread.interrupt();
+        }
+    }
+}

main/src/main/java/sd/model/Event.java

@@ -1,61 +0,0 @@
-package sd.model;
-
-import java.io.Serializable;
-
-/**
- * Represents an event in the discrete event simulation.
- * Events are ordered by timestamp for sequential processing.
- */
-public class Event implements Comparable<Event>, Serializable {
-    private static final long serialVersionUID = 1L;
-    
-    private final double timestamp;  // Time when the event occurs
-    private final EventType type;
-    private final Object data;  // Data associated with the event (e.g., Vehicle, traffic light id, etc.)
-    private final String location;  // Intersection or location where the event occurs
-    
-    public Event(double timestamp, EventType type, Object data, String location) {
-        this.timestamp = timestamp;
-        this.type = type;
-        this.data = data;
-        this.location = location;
-    }
-    
-    public Event(double timestamp, EventType type, Object data) {
-        this(timestamp, type, data, null);
-    }
-    
-    @Override
-    public int compareTo(Event other) {
-        // Sort by timestamp (earlier events have priority)
-        int cmp = Double.compare(this.timestamp, other.timestamp);
-        if (cmp == 0) {
-            // If timestamps are equal, sort by event type
-            return this.type.compareTo(other.type);
-        }
-        return cmp;
-    }
-    
-    // Getters
-    public double getTimestamp() {
-        return timestamp;
-    }
-    
-    public EventType getType() {
-        return type;
-    }
-    
-    public Object getData() {
-        return data;
-    }
-    
-    public String getLocation() {
-        return location;
-    }
-    
-    @Override
-    public String toString() {
-        return String.format("Event{t=%.2f, type=%s, loc=%s}", 
-                           timestamp, type, location);
-    }
-}

main/src/main/java/sd/model/EventType.java

@@ -1,13 +0,0 @@
-package sd.model;
-
-/**
- * Enumeration representing event types in the simulation.
- */
-public enum EventType {
-    VEHICLE_ARRIVAL,           // Vehicle arrives at an intersection
-    TRAFFIC_LIGHT_CHANGE,      // Traffic light changes state (green/red)
-    CROSSING_START,            // Vehicle starts crossing the intersection
-    CROSSING_END,              // Vehicle finishes crossing
-    VEHICLE_GENERATION,        // New vehicle is generated in the system
-    STATISTICS_UPDATE          // Time to send statistics to dashboard
-}

main/src/main/java/sd/model/Intersection.java

@@ -7,22 +7,65 @@ import java.util.Map;
 
 /**
  * Represents an intersection in the traffic simulation.
- * 
- * Each intersection coordinates multiple traffic lights - one for each direction -
- * and handles routing vehicles based on their next destination.
+ * * An Intersection acts as a central hub. It does not control logic itself,
+ * but it *owns* and *manages* a set of {@link TrafficLight} objects.
+ * * Its primary responsibilities are:
+ * 1.  Holding a {@link TrafficLight} for each direction ("North", "East", etc.).
+ * 2.  Maintaining a {@code routing} table that maps a vehicle's *next*
+ * destination (e.g., "Cr3") to a specific *direction* at *this*
+ * intersection (e.g., "East").
+ * 3.  Receiving incoming vehicles and placing them in the correct
+ * traffic light's queue based on the routing table.
+ * 4.  Tracking aggregate statistics for all traffic passing through it.
  */
 public class Intersection {
 
-    // Identity and configuration
-    private final String id;  // ex. "Cr1", "Cr2"
-    private final Map<String, TrafficLight> trafficLights;  // direction -> light
-    private final Map<String, String> routing;              // destination -> direction
+    // --- Identity and configuration ---
+    
+    /**
+     * Unique identifier for the intersection (e.g., "Cr1", "Cr2").
+     */
+    private final String id;
+    
+    /**
+     * A map holding all traffic lights managed by this intersection.
+     * Key: Direction (String, e.g., "North", "East").
+     * Value: The {@link TrafficLight} object for that direction.
+     */
+    private final Map<String, TrafficLight> trafficLights;
+    
+    /**
+     * The routing table for this intersection.
+     * Key: The *next* destination ID (String, e.g., "Cr3", "S" for exit).
+     * Value: The *direction* (String, e.g., "East") a vehicle must take
+     * at *this* intersection to reach that destination.
+     */
+    private final Map<String, String> routing;
 
-    // Stats
+    // --- Statistics ---
+    
+    /**
+     * Total number of vehicles that have been received by this intersection.
+     */
     private int totalVehiclesReceived;
+    
+    /**
+     * Total number of vehicles that have successfully passed through (sent from) this intersection.
+     */
     private int totalVehiclesSent;
+    
+    /**
+     * A running average of the waiting time for vehicles at this intersection.
+     * Note: This calculation might be simplified.
+     */
     private double averageWaitingTime;
 
+    /**
+     * Constructs a new Intersection with a given ID.
+     * Initializes empty maps for traffic lights and routing.
+     *
+     * @param id The unique identifier for this intersection (e.g., "Cr1").
+     */
     public Intersection(String id) {
         this.id = id;
         this.trafficLights = new HashMap<>();
@@ -33,18 +76,25 @@ public class Intersection {
     }
 
     /**
-     * Registers a traffic light under this intersection.
-     * The light is identified by its direction (ex., "North", "East").
+     * Registers a new {@link TrafficLight} with this intersection.
+     * The light is mapped by its direction.
+     *
+     * @param trafficLight The {@link TrafficLight} object to add.
      */
     public void addTrafficLight(TrafficLight trafficLight) {
         trafficLights.put(trafficLight.getDirection(), trafficLight);
     }
 
     /**
-     * Defines how vehicles should be routed through this intersection.
+     * Defines a routing rule for this intersection.
+     * * This method builds the routing table. For example, calling
+     * {@code configureRoute("Cr3", "East")} means "Any vehicle
+     * arriving here whose next destination is 'Cr3' should be sent to
+     * the 'East' traffic light queue."
      *
-     * @param nextDestination The next intersection or exit on the vehicle's route
-     * @param direction       The direction (traffic light) vehicles should take
+     * @param nextDestination The ID of the *next* intersection or exit (e.g., "Cr3", "S").
+     * @param direction       The direction (and thus, the traffic light)
+     * at *this* intersection to use (e.g., "East").
      */
     public void configureRoute(String nextDestination, String direction) {
         routing.put(nextDestination, direction);
@@ -52,36 +102,86 @@ public class Intersection {
 
     /**
      * Accepts an incoming vehicle and places it in the correct queue.
-     * If the route or traffic light can't be found, logs an error.
+     * * This method:
+     * 1. Increments the {@link #totalVehiclesReceived} counter.
+     * 2. Advances the vehicle's route (since it just arrived here)
+     * 3. Gets the vehicle's *next* destination (from {@link Vehicle#getCurrentDestination()}).
+     * 4. Uses the {@link #routing} map to find the correct *direction* for that destination.
+     * 5. Adds the vehicle to the queue of the {@link TrafficLight} for that direction.
+     *
+     * @param vehicle The {@link Vehicle} arriving at the intersection.
      */
     public void receiveVehicle(Vehicle vehicle) {
         totalVehiclesReceived++;
 
+        // Note: Route advancement is handled by SimulationEngine.handleVehicleArrival()
+        // before calling this method, so we don't advance here.
+        
         String nextDestination = vehicle.getCurrentDestination();
+        
+        // Check if vehicle reached final destination
+        if (nextDestination == null) {
+            System.out.printf("[%s] Vehicle %s reached final destination%n", 
+                this.id, vehicle.getId());
+            return;
+        }
+        
         String direction = routing.get(nextDestination);
 
         if (direction != null && trafficLights.containsKey(direction)) {
+            // Found a valid route and light, add vehicle to the queue
             trafficLights.get(direction).addVehicle(vehicle);
         } else {
+            // Routing error: No rule for this destination or no light for that direction
             System.err.printf(
-                "Routing error: could not place vehicle %s (destination: %s)%n",
-                vehicle.getId(), nextDestination
+                "Routing error at %s: could not place vehicle %s (destination: %s, found direction: %s)%n",
+                this.id, vehicle.getId(), nextDestination, direction
             );
         }
     }
 
-    /** Returns the traffic light controlling the given direction, if any. */
+    /**
+     * Returns the direction a vehicle should take to reach a given destination.
+     *
+     * @param destination The next destination (e.g., "Cr3", "S").
+     * @return The direction (e.g., "East"), or null if no route is configured.
+     */
+    public String getDirectionForDestination(String destination) {
+        return routing.get(destination);
+    }
+
+    /**
+     * Returns the traffic light controlling the given direction.
+     *
+     * @param direction The direction (e.g., "North").
+     * @return The {@link TrafficLight} object, or null if no light exists
+     * for that direction.
+     */
     public TrafficLight getTrafficLight(String direction) {
         return trafficLights.get(direction);
     }
 
-    /** Returns all traffic lights belonging to this intersection. */
+    /**
+     * Returns a list of all traffic lights managed by this intersection.
+     *
+     * @return A new {@link List} containing all {@link TrafficLight} objects.
+     */
     public List<TrafficLight> getTrafficLights() {
+        // Return a copy to prevent external modification of the internal map's values
         return new ArrayList<>(trafficLights.values());
     }
 
-    /** Returns the total number of vehicles currently queued across all directions. */
+    /**
+     * Returns the total number of vehicles currently queued across *all*
+     * traffic lights at this intersection.
+     *
+     * @return The sum of all queue sizes.
+     */
     public int getTotalQueueSize() {
+        // Uses Java Stream API:
+        // 1. trafficLights.values().stream() - Get a stream of TrafficLight objects
+        // 2. .mapToInt(TrafficLight::getQueueSize) - Convert each light to its queue size (an int)
+        // 3. .sum() - Sum all the integers
         return trafficLights.values().stream()
                 .mapToInt(TrafficLight::getQueueSize)
                 .sum();
@@ -89,35 +189,68 @@ public class Intersection {
 
     // --- Stats and getters ---
 
+    /**
+     * @return The unique ID of this intersection.
+     */
     public String getId() {
         return id;
     }
 
+    /**
+     * @return The total number of vehicles that have arrived at this intersection.
+     */
     public int getTotalVehiclesReceived() {
         return totalVehiclesReceived;
     }
 
+    /**
+     * @return The total number of vehicles that have successfully
+     * departed from this intersection.
+     */
     public int getTotalVehiclesSent() {
         return totalVehiclesSent;
     }
 
+    /**
+     * Increments the counter for vehicles that have successfully departed.
+     * This is typically called by the {@link sd.engine.SimulationEngine}
+     * after a vehicle finishes crossing.
+     */
     public void incrementVehiclesSent() {
         totalVehiclesSent++;
     }
 
+    /**
+     * @return The running average of vehicle waiting time at this intersection.
+     */
     public double getAverageWaitingTime() {
         return averageWaitingTime;
     }
 
     /**
-     * Updates the running average waiting time with a new sample.
+     * Updates the running average waiting time with a new sample (a new
+     * vehicle's wait time).
+     * * Uses an incremental/weighted average formula:
+     * NewAvg = (OldAvg * (N-1) + NewValue) / N
+     * where N is the total number of vehicles sent.
+     *
+     * @param newTime The waiting time (in seconds) of the vehicle that just
+     * departed.
      */
     public void updateAverageWaitingTime(double newTime) {
-        // Weighted incremental average (avoids recalculating from scratch)
-        averageWaitingTime = (averageWaitingTime * (totalVehiclesSent - 1) + newTime)
-                           / totalVehiclesSent;
+        // Avoid division by zero if this is called before any vehicle is sent
+        if (totalVehiclesSent > 0) {
+            averageWaitingTime = (averageWaitingTime * (totalVehiclesSent - 1) + newTime)
+                               / totalVehiclesSent;
+        } else if (totalVehiclesSent == 1) {
+             // This is the first vehicle
+            averageWaitingTime = newTime;
+        }
     }
 
+    /**
+     * @return A string summary of the intersection's current state.
+     */
     @Override
     public String toString() {
         return String.format(
@@ -129,4 +262,4 @@ public class Intersection {
             totalVehiclesSent
         );
     }
-}
+}

main/src/main/java/sd/model/Message.java

@@ -0,0 +1,154 @@
+package sd.model;
+
+import java.util.UUID;
+
+import sd.protocol.MessageProtocol;
+
+/**
+ * Represents a message exchanged between processes in the distributed simulation.
+ * Each message has a unique ID, a type, a sender, a destination, and a payload.
+ * This class implements {@link MessageProtocol} which extends Serializable for network transmission.
+ */
+public class Message implements MessageProtocol {
+    
+    private static final long serialVersionUID = 1L;
+    
+    /**
+     * Unique identifier for this message.
+     */
+    private final String messageId;
+    
+    /**
+     * The type of this message (e.g., VEHICLE_TRANSFER, STATS_UPDATE).
+     */
+    private final MessageType type;
+    
+    /**
+     * Identifier of the process that sent this message.
+     */
+    private final String senderId;
+    
+    /**
+     * Identifier of the destination process. Can be null for broadcast messages.
+     */
+    private final String destinationId;
+    
+    /**
+     * The actual data being transmitted. Type depends on the message type.
+     */
+    private final Object payload;
+    
+    /**
+     * Timestamp when this message was created (simulation time or real time).
+     */
+    private final long timestamp;
+    
+    /**
+     * Creates a new message with all parameters.
+     *
+     * @param type The message type
+     * @param senderId The ID of the sending process
+     * @param destinationId The ID of the destination process (null for broadcast)
+     * @param payload The message payload
+     * @param timestamp The timestamp of message creation
+     */
+    public Message(MessageType type, String senderId, String destinationId, 
+                   Object payload, long timestamp) {
+        this.messageId = UUID.randomUUID().toString();
+        this.type = type;
+        this.senderId = senderId;
+        this.destinationId = destinationId;
+        this.payload = payload;
+        this.timestamp = timestamp;
+    }
+    
+    /**
+     * Creates a new message with current system time as timestamp.
+     *
+     * @param type The message type
+     * @param senderId The ID of the sending process
+     * @param destinationId The ID of the destination process
+     * @param payload The message payload
+     */
+    public Message(MessageType type, String senderId, String destinationId, Object payload) {
+        this(type, senderId, destinationId, payload, System.currentTimeMillis());
+    }
+    
+    /**
+     * Creates a broadcast message (no specific destination).
+     *
+     * @param type The message type
+     * @param senderId The ID of the sending process
+     * @param payload The message payload
+     */
+    public Message(MessageType type, String senderId, Object payload) {
+        this(type, senderId, null, payload, System.currentTimeMillis());
+    }
+    
+    //Getters
+    
+    public String getMessageId() {
+        return messageId;
+    }
+    
+    public MessageType getType() {
+        return type;
+    }
+    
+    public String getSenderId() {
+        return senderId;
+    }
+    
+    public String getDestinationId() {
+        return destinationId;
+    }
+    
+    public Object getPayload() {
+        return payload;
+    }
+    
+    public long getTimestamp() {
+        return timestamp;
+    }
+    
+    /**
+     * Checks if this is a broadcast message (no specific destination).
+     *
+     * @return true if destinationId is null, false otherwise
+     */
+    public boolean isBroadcast() {
+        return destinationId == null;
+    }
+    
+    /**
+     * Gets the payload cast to a specific type.
+     * Use with caution and ensure type safety.
+     *
+     * @param <T> The expected payload type
+     * @return The payload cast to type T
+     * @throws ClassCastException if the payload is not of type T
+     */
+    @SuppressWarnings("unchecked")
+    public <T> T getPayloadAs(Class<T> clazz) {
+        return (T) payload;
+    }
+    
+    // Impl MessageProtocol interface
+    @Override
+    public String getSourceNode() {
+        return senderId;
+    }
+    
+    @Override
+    public String getDestinationNode() {
+        return destinationId;
+    }
+    
+    @Override
+    public String toString() {
+        return String.format("Message[id=%s, type=%s, from=%s, to=%s, timestamp=%d]",
+                           messageId, type, senderId, 
+                           destinationId != null ? destinationId : "BROADCAST",
+                           timestamp);
+    }
+}

main/src/main/java/sd/model/MessageType.java

@@ -0,0 +1,87 @@
+package sd.model;
+
+/**
+ * Enumeration representing all possible message types for distributed communication.
+ * These types are used for inter-process communication between different components
+ * of the distributed traffic simulation system.
+ */
+public enum MessageType {
+    
+    /**
+     * Message to transfer a vehicle between intersections or processes.
+     * Payload: Vehicle object with current state
+     */
+    VEHICLE_TRANSFER,
+    
+    /**
+     * Message to update statistics across the distributed system.
+     * Payload: Statistics data (waiting times, queue sizes, etc.)
+     */
+    STATS_UPDATE,
+    
+    /**
+     * Message to synchronize simulation start time across all processes.
+     * Payload: Start timestamp (long milliseconds)
+     */
+    SIMULATION_START,
+    
+    /**
+     * Message to synchronize traffic light states between processes.
+     * Payload: TrafficLight state and timing information
+     */
+    TRAFFIC_LIGHT_SYNC,
+    
+    /**
+     * Heartbeat message to check if a process is alive.
+     * Payload: Process ID and timestamp
+     */
+    HEARTBEAT,
+    
+    /**
+     * Request to join the distributed simulation.
+     * Payload: Process information and capabilities
+     */
+    JOIN_REQUEST,
+    
+    /**
+     * Response to a join request.
+     * Payload: Acceptance status and configuration
+     */
+    JOIN_RESPONSE,
+    
+    /**
+     * Message to notify about a new vehicle generation.
+     * Payload: Vehicle generation parameters
+     */
+    VEHICLE_SPAWN,
+    
+    /**
+     * Message to request the current state of an intersection.
+     * Payload: Intersection ID
+     */
+    STATE_REQUEST,
+    
+    /**
+     * Response containing the current state of an intersection.
+     * Payload: Complete intersection state
+     */
+    STATE_RESPONSE,
+    
+    /**
+     * Message to signal shutdown of a process.
+     * Payload: Process ID and reason
+     */
+    SHUTDOWN,
+    
+    /**
+     * Acknowledgment message for reliable communication.
+     * Payload: Message ID being acknowledged
+     */
+    ACK,
+    
+    /**
+     * Error message to report problems in the distributed system.
+     * Payload: Error description and context
+     */
+    ERROR
+}

main/src/main/java/sd/model/TrafficLight.java

@@ -1,6 +1,8 @@
 package sd.model;
 
+import java.util.HashMap;
 import java.util.LinkedList;
+import java.util.Map;
 import java.util.Queue;
 import java.util.concurrent.locks.Condition;
 import java.util.concurrent.locks.Lock;
@@ -8,173 +10,323 @@ import java.util.concurrent.locks.ReentrantLock;
 
 /**
  * Represents a single traffic light controlling one direction at an intersection.
- * 
- * Each light maintains its own queue of vehicles and alternates between
- * green and red states. It's designed to be thread-safe (maybe...), so multiple
- * threads (like vehicles or controllers) can safely interact with it.
+ * * Each light maintains its own queue of {@link Vehicle} objects and
+ * alternates between {@link TrafficLightState#GREEN} and
+ * {@link TrafficLightState#RED} states.
+ * * This class is designed to be thread-safe for a potential concurrent
+ * simulation (though the current engine {@link sd.engine.SimulationEngine}
+ * is single-threaded). It uses a {@link ReentrantLock} to protect its
+ * internal state (the queue and the light state) from simultaneous access.
+ * * The {@link Condition} variables ({@code vehicleAdded}, {@code lightGreen})
+ * are included for a concurrent model where:
+ * - A "vehicle" thread might wait on {@code lightGreen} until the light changes.
+ * - A "controller" thread might wait on {@code vehicleAdded} to know when to
+ * process a queue.
+ * (Note: These Conditions are *not* used by the current discrete-event engine).
  */
 public class TrafficLight {
 
-    // Identity and configuration
-    private final String id;          // ex. "Cr1-N"
-    private final String direction;   // ex. "North", "South", etc.
+    // --- Identity and configuration ---
+    
+    /**
+     * Unique identifier for the light (e.g., "Cr1-N").
+     */
+    private final String id;
+    
+    /**
+     * The direction this light controls (e.g., "North", "South").
+     */
+    private final String direction;
+    
+    /**
+     * The current state of the light (GREEN or RED).
+     */
     private TrafficLightState state;
 
-    // Vehicle management
+    // --- Vehicle management ---
+    
+    /**
+     * The queue of vehicles waiting at this light.
+     * {@link LinkedList} is used as it's a standard {@link Queue} implementation.
+     */
     private final Queue<Vehicle> queue;
 
-    // Synchronization primitives
+    // --- Synchronization primitives (for thread-safety) ---
+    
+    /**
+     * A lock to protect all mutable state ({@link #queue} and {@link #state})
+     * from concurrent access. Any method reading or writing these fields
+     * *must* acquire this lock first.
+     */
     private final Lock lock;
+    
+    /**
+     * A condition variable for a potential concurrent model.
+     * It could be used to signal threads (e.g., a controller) that
+     * a new vehicle has been added to the queue.
+     * (Not used in the current discrete-event engine).
+     */
     private final Condition vehicleAdded;
+    
+    /**
+     * A condition variable for a potential concurrent model.
+     * It could be used to signal waiting vehicle threads that the
+     * light has just turned GREEN.
+     * (Not used in the current discrete-event engine).
+     */
     private final Condition lightGreen;
 
-    // Timing configuration (seconds)
+    // --- Timing configuration ---
+    
+    /**
+     * The duration (in seconds) this light stays GREEN.
+     */
     private double greenTime;
+    
+    /**
+     * The duration (in seconds) this light stays RED.
+     */
     private double redTime;
 
-    // Basic stats
+    // --- Statistics ---
+    
+    /**
+     * Counter for the total number of vehicles that have
+     * been dequeued (processed) by this light.
+     */
     private int totalVehiclesProcessed;
+    
+    /**
+     * Track when vehicles arrive at this light for wait time calculation.
+     * Maps vehicle ID to arrival timestamp (milliseconds).
+     */
+    private final Map<String, Long> vehicleArrivalTimes;
 
+    /**
+     * Constructs a new TrafficLight.
+     *
+     * @param id The unique ID (e.g., "Cr1-N").
+     * @param direction The direction (e.g., "North").
+     * @param greenTime The duration of the GREEN state in seconds.
+     * @param redTime The duration of the RED state in seconds.
+     */
     public TrafficLight(String id, String direction, double greenTime, double redTime) {
         this.id = id;
         this.direction = direction;
-        this.state = TrafficLightState.RED;
+        this.state = TrafficLightState.RED; // All lights start RED
         this.queue = new LinkedList<>();
 
+        // Initialize synchronization objects
         this.lock = new ReentrantLock();
         this.vehicleAdded = lock.newCondition();
         this.lightGreen = lock.newCondition();
 
         this.greenTime = greenTime;
         this.redTime = redTime;
+        this.vehicleArrivalTimes = new HashMap<>();
         this.totalVehiclesProcessed = 0;
     }
 
     /**
-     * Adds a vehicle to the waiting queue.
-     * Signals any waiting threads that a new vehicle has arrived.
+     * Adds a vehicle to the *end* of the waiting queue.
+     * This method is thread-safe.
+     *
+     * @param vehicle The {@link Vehicle} to add.
      */
     public void addVehicle(Vehicle vehicle) {
-        lock.lock();
+        lock.lock(); // Acquire the lock
         try {
-            queue.offer(vehicle);
-            vehicleAdded.signalAll();
+            queue.offer(vehicle); // Add vehicle to queue
+            vehicleArrivalTimes.put(vehicle.getId(), System.currentTimeMillis());
+            vehicleAdded.signalAll(); // Signal (for concurrent models)
         } finally {
-            lock.unlock();
+            lock.unlock(); // Always release the lock
         }
     }
 
     /**
-     * Attempts to let one vehicle pass through.
-     * Only works if the light is green; otherwise returns null.
+     * Removes and returns the {@link Vehicle} from the *front* of the queue.
+     * * This only succeeds if:
+     * 1. The light's state is {@link TrafficLightState#GREEN}.
+     * 2. The queue is not empty.
+     * * If these conditions are not met, it returns {@code null}.
+     * This method is thread-safe.
+     *
+     * @return The {@link Vehicle} at the front of the queue, or {@code null}
+     * if the light is RED or the queue is empty.
      */
     public Vehicle removeVehicle() {
-        lock.lock();
+        lock.lock(); // Acquire the lock
         try {
             if (state == TrafficLightState.GREEN && !queue.isEmpty()) {
-                Vehicle vehicle = queue.poll();
-                totalVehiclesProcessed++;
+                Vehicle vehicle = queue.poll(); // Remove vehicle from queue
+                if (vehicle != null) {
+                    totalVehiclesProcessed++;
+                    
+                    // Calculate wait time (time spent in queue)
+                    Long arrivalTime = vehicleArrivalTimes.remove(vehicle.getId());
+                    if (arrivalTime != null) {
+                        double waitTimeSeconds = (System.currentTimeMillis() - arrivalTime) / 1000.0;
+                        vehicle.addWaitingTime(waitTimeSeconds);
+                    }
+                }
                 return vehicle;
             }
-            return null;
+            return null; // Light is RED or queue is empty
         } finally {
-            lock.unlock();
+            lock.unlock(); // Always release the lock
         }
     }
 
     /**
-     * Changes the light’s state (ex., RED -> GREEN).
-     * When the light turns green, waiting threads are notified.
-     *                  ¯\_(ツ)_/¯
+     * Changes the light’s state (e.g., RED -> GREEN).
+     * If the new state is GREEN, it signals any waiting threads
+     * (for a potential concurrent model).
+     * This method is thread-safe.
+     *
+     * @param newState The {@link TrafficLightState} to set.
      */
     public void changeState(TrafficLightState newState) {
-        lock.lock();
+        lock.lock(); // Acquire the lock
         try {
             this.state = newState;
             if (newState == TrafficLightState.GREEN) {
-                lightGreen.signalAll();
+                lightGreen.signalAll(); // Signal (for concurrent models)
             }
         } finally {
-            lock.unlock();
+            lock.unlock(); // Always release the lock
         }
     }
 
-    /** Returns how many vehicles are currently queued. */
+    /**
+     * Returns how many vehicles are currently in the queue.
+     * This method is thread-safe.
+     * * @return The size of the queue.
+     */
     public int getQueueSize() {
-        lock.lock();
+        lock.lock(); // Acquire the lock
         try {
             return queue.size();
         } finally {
-            lock.unlock();
+            lock.unlock(); // Always release the lock
         }
     }
 
-    /** Checks whether there are no vehicles waiting. */
+    /**
+     * Checks whether the queue is empty.
+     * This method is thread-safe.
+     *
+     * @return {@code true} if the queue has no vehicles, {@code false} otherwise.
+     */
     public boolean isQueueEmpty() {
-        lock.lock();
+        lock.lock(); // Acquire the lock
         try {
             return queue.isEmpty();
         } finally {
-            lock.unlock();
+            lock.unlock(); // Always release the lock
         }
     }
 
     // --- Getters & Setters ---
 
+    /**
+     * @return The unique ID of this light (e.g., "Cr1-N").
+     */
     public String getId() {
         return id;
     }
 
+    /**
+     * @return The direction this light controls (e.g., "North").
+     */
     public String getDirection() {
         return direction;
     }
 
+    /**
+     * Gets the current state of the light (GREEN or RED).
+     * This method is thread-safe.
+     *
+     * @return The current {@link TrafficLightState}.
+     */
     public TrafficLightState getState() {
-        lock.lock();
+        lock.lock(); // Acquire the lock
         try {
             return state;
         } finally {
-            lock.unlock();
+            lock.unlock(); // Always release the lock
         }
     }
 
+    /**
+     * @return The configured GREEN light duration in seconds.
+     */
     public double getGreenTime() {
         return greenTime;
     }
 
+    /**
+     * Sets the GREEN light duration.
+     * @param greenTime The new duration in seconds.
+     */
     public void setGreenTime(double greenTime) {
         this.greenTime = greenTime;
     }
 
+    /**
+     * @return The configured RED light duration in seconds.
+     */
     public double getRedTime() {
         return redTime;
     }
 
+    /**
+     * Sets the RED light duration.
+     * @param redTime The new duration in seconds.
+     */
     public void setRedTime(double redTime) {
         this.redTime = redTime;
     }
 
+    /**
+     * @return The total number of vehicles processed (dequeued) by this light.
+     */
     public int getTotalVehiclesProcessed() {
+        // Note: This read is not locked, assuming it's okay
+        // for it to be "eventually consistent" for stats.
+        // For strict accuracy, it should also be locked.
         return totalVehiclesProcessed;
     }
 
+    /**
+     * @return The {@link Lock} object for advanced synchronization.
+     */
     public Lock getLock() {
         return lock;
     }
 
+    /**
+     * @return The {@link Condition} for vehicle additions.
+     */
     public Condition getVehicleAdded() {
         return vehicleAdded;
     }
 
+    /**
+     * @return The {@link Condition} for the light turning green.
+     */
     public Condition getLightGreen() {
         return lightGreen;
     }
 
+    /**
+     * @return A string summary of the light's current state.
+     */
     @Override
     public String toString() {
         return String.format(
             "TrafficLight{id='%s', direction='%s', state=%s, queueSize=%d}",
-            id, direction, state, getQueueSize()
+            id, direction, getState(), getQueueSize() // Use getters for thread-safety
         );
     }
-}
+}

main/src/main/java/sd/model/TrafficLightState.java

@@ -1,9 +1,17 @@
 package sd.model;
 
 /**
- * Enumeration representing the state of a traffic light.
+ * Enumeration representing the two possible states of a {@link TrafficLight}.
  */
 public enum TrafficLightState {
-    GREEN,      // Allows passage
-    RED         // Blocks passage
-}
+    
+    /**
+     * The light is GREEN, allowing vehicles to pass (be dequeued).
+     */
+    GREEN,
+    
+    /**
+     * The light is RED, blocking vehicles (they remain in the queue).
+     */
+    RED
+}

main/src/main/java/sd/model/Vehicle.java

@@ -7,39 +7,92 @@ import java.util.List;
 /**
  * Represents a single vehicle moving through the simulation.
  *
- * Each vehicle has a route - a sequence of intersections it will pass through -
- * and keeps track of how long it has waited and traveled overall.
- * 
- * Serializable so it can be sent between processes or nodes over sockets. type shit
+ * This class is a data object that holds the state of a vehicle, including:
+ * - Its unique ID, type, and entry time.
+ * - Its complete, pre-determined {@code route} (a list of intersection IDs).
+ * - Its current position in the route ({@code currentRouteIndex}).
+ * - Metrics for total time spent waiting at red lights and time spent crossing.
+ * * This object is passed around the simulation, primarily inside message
+ * payloads and stored in {@link TrafficLight} queues.
+ * * Implements {@link Serializable} so it can be sent between processes
+ * or nodes (e.g., over a socket in a distributed version of the simulation).
  */
 public class Vehicle implements Serializable {
     private static final long serialVersionUID = 1L;
 
-    // Identity and configuration
+    // --- Identity and configuration ---
+
+    /**
+     * Unique identifier for the vehicle (e.g., "V1", "V2").
+     */
     private final String id;
+
+    /**
+     * The type of vehicle (BIKE, LIGHT, HEAVY).
+     */
     private final VehicleType type;
-    private final double entryTime;          // When it entered the system
-    private final List<String> route;        // ex., ["Cr1", "Cr3", "S"]
-    private int currentRouteIndex;           // Current position in the route
 
-    // Metrics
-    private double totalWaitingTime;         // Total time spent waiting at red lights
-    private double totalCrossingTime;        // Time spent actually moving between intersections
+    /**
+     * The simulation time (in seconds) when the vehicle was generated.
+     */
+    private final double entryTime;
 
+    /**
+     * The complete, ordered list of destinations (intersection IDs and the
+     * final exit "S"). Example: ["Cr1", "Cr3", "S"].
+     */
+    private final List<String> route;
+
+    /**
+     * An index that tracks the vehicle's progress along its {@link #route}.
+     * {@code route.get(currentRouteIndex)} is the vehicle's *current*
+     * destination (i.e., the one it is traveling *towards* or *arriving at*).
+     */
+    private int currentRouteIndex;
+
+    // --- Metrics ---
+
+    /**
+     * The total accumulated time (in seconds) this vehicle has spent
+     * waiting at red lights.
+     */
+    private double totalWaitingTime;
+
+    /**
+     * The total accumulated time (in seconds) this vehicle has spent
+     * actively crossing intersections.
+     */
+    private double totalCrossingTime;
+
+    /**
+     * Constructs a new Vehicle.
+     *
+     * @param id        The unique ID for the vehicle.
+     * @param type      The {@link VehicleType}.
+     * @param entryTime The simulation time when the vehicle is created.
+     * @param route     The complete list of destination IDs (e.t., ["Cr1", "Cr2",
+     *                  "S"]).
+     */
     public Vehicle(String id, VehicleType type, double entryTime, List<String> route) {
         this.id = id;
         this.type = type;
         this.entryTime = entryTime;
+        // Create a copy of the route list to ensure immutability
         this.route = new ArrayList<>(route);
-        this.currentRouteIndex = 0;
+        this.currentRouteIndex = 0; // Starts at the first destination
         this.totalWaitingTime = 0.0;
         this.totalCrossingTime = 0.0;
     }
 
     /**
-     * Moves the vehicle to the next stop in its route.
-     * 
-     * @return true if there are still destinations ahead, false if the route is finished
+     * Advances the vehicle to the next stop in its route by
+     * incrementing the {@link #currentRouteIndex}.
+     * * This is typically called *after* a vehicle *arrives* at an intersection,
+     * to set its *next* destination before it is queued.
+     *
+     * @return {@code true} if there is still at least one more destination
+     *         in the route, {@code false} if the vehicle has passed its
+     *         final destination.
      */
     public boolean advanceRoute() {
         currentRouteIndex++;
@@ -47,71 +100,120 @@ public class Vehicle implements Serializable {
     }
 
     /**
-     * Gets the current destination (the next intersection or exit).
-     * Returns null if the route is already complete.
+     * Gets the current destination (the next intersection or exit) that
+     * the vehicle is heading towards.
+     *
+     * @return The ID of the current destination (e.g., "Cr1"), or
+     *         {@code null} if the route is complete.
      */
     public String getCurrentDestination() {
         return (currentRouteIndex < route.size()) ? route.get(currentRouteIndex) : null;
     }
 
-    /** Returns true if the vehicle has completed its entire route. */
+    /**
+     * Checks if the vehicle has completed its entire route.
+     *
+     * @return {@code true} if the route index is at or past the end
+     *         of the route list, {@code false} otherwise.
+     */
     public boolean hasReachedEnd() {
         return currentRouteIndex >= route.size();
     }
 
     // --- Getters and metrics management ---
 
+    /**
+     * @return The vehicle's unique ID.
+     */
     public String getId() {
         return id;
     }
 
+    /**
+     * @return The vehicle's {@link VehicleType}.
+     */
     public VehicleType getType() {
         return type;
     }
 
+    /**
+     * @return The simulation time when the vehicle entered the system.
+     */
     public double getEntryTime() {
         return entryTime;
     }
 
+    /**
+     * @return A *copy* of the vehicle's complete route.
+     */
     public List<String> getRoute() {
+        // Return a copy to prevent external modification
         return new ArrayList<>(route);
     }
 
+    /**
+     * @return The current index pointing to the vehicle's destination in its route
+     *         list.
+     */
     public int getCurrentRouteIndex() {
         return currentRouteIndex;
     }
 
+    /**
+     * @return The total accumulated waiting time in seconds.
+     */
     public double getTotalWaitingTime() {
         return totalWaitingTime;
     }
 
+    /**
+     * Adds a duration to the vehicle's total waiting time.
+     * This is called by the simulation engine when a vehicle
+     * starts crossing an intersection.
+     *
+     * @param time The duration (in seconds) to add.
+     */
     public void addWaitingTime(double time) {
         totalWaitingTime += time;
     }
 
+    /**
+     * @return The total accumulated crossing time in seconds.
+     */
     public double getTotalCrossingTime() {
         return totalCrossingTime;
     }
 
+    /**
+     * Adds a duration to the vehicle's total crossing time.
+     * This is called by the simulation engine when a vehicle
+     * finishes crossing an intersection.
+     *
+     * @param time The duration (in seconds) to add.
+     */
     public void addCrossingTime(double time) {
         totalCrossingTime += time;
     }
 
     /**
-     * Calculates how long the vehicle has been in the system so far.
+     * Calculates the vehicle's total time spent in the system so far.
+     * This is a "live" calculation.
      *
-     * @param currentTime the current simulation time
-     * @return total elapsed time since the vehicle entered
+     * @param currentTime The current simulation time.
+     * @return The total elapsed time (in seconds) since the vehicle
+     *         was generated ({@code currentTime - entryTime}).
      */
     public double getTotalTravelTime(double currentTime) {
         return currentTime - entryTime;
     }
 
+    /**
+     * @return A string summary of the vehicle's current state.
+     */
     @Override
     public String toString() {
         return String.format(
-            "Vehicle{id='%s', type=%s, next='%s', route=%s}",
-            id, type, getCurrentDestination(), route
-        );
+                "Vehicle{id='%s', type=%s, next='%s', route=%s}",
+                id, type, getCurrentDestination(), route);
     }
-}
+}

main/src/main/java/sd/model/VehicleType.java

@@ -1,10 +1,27 @@
 package sd.model;
 
 /**
- * Enumeration representing vehicle types in the simulation.
+ * Enumeration representing the different types of vehicles in the simulation.
+ * Each type can have different properties, such as crossing time
+ * and generation probability, defined in {@link sd.config.SimulationConfig}.
  */
 public enum VehicleType {
-    BIKE,  // Motorcycle
-    LIGHT,      // Light vehicle (car)
-    HEAVY       // Heavy vehicle (truck, bus)
-}
+    
+    /**
+     * A bike or motorcycle.
+     * Typically has a short crossing time.
+     */
+    BIKE,
+    
+    /**
+     * A standard light vehicle, such as a car.
+     * This is usually the most common type.
+     */
+    LIGHT,
+    
+    /**
+     * A heavy vehicle, such as a truck or bus.
+     * Typically has a long crossing time.
+     */
+    HEAVY
+}

main/src/main/java/sd/protocol/MessageProtocol.java

@@ -0,0 +1,41 @@
+package sd.protocol;
+
+import java.io.Serializable;
+import sd.model.MessageType; // Assuming MessageType is in sd.model or sd.protocol
+
+/**
+ * Interface defining the contract for all messages exchanged in the simulator.
+ * Ensures that any message can be identified and routed.
+ * * This interface extends Serializable to allow objects that implement it
+ * to be sent over Sockets (ObjectOutputStream).
+ *
+ */
+public interface MessageProtocol extends Serializable {
+
+    /**
+     * Returns the type of the message, indicating its purpose.
+     * @return The MessageType (e.g., VEHICLE_TRANSFER, STATS_UPDATE).
+     */
+    MessageType getType();
+
+    /**
+     * Returns the data object (payload) that this message carries.
+     * The type of object will depend on the MessageType.
+     * * - If getType() == VEHICLE_TRANSFER, the payload will be a {@link sd.model.Vehicle} object.
+     * - If getType() == STATS_UPDATE, the payload will be a statistics object.
+     * * @return The data object (payload), which must also be Serializable.
+     */
+    Object getPayload();
+
+    /**
+     * Returns the ID of the node (Process) that sent this message.
+     * @return String (e.g., "Cr1", "Cr5", "S").
+     */
+    String getSourceNode();
+
+    /**
+     * Returns the ID of the destination node (Process) for this message.
+     * @return String (e.g., "Cr2", "DashboardServer").
+     */
+    String getDestinationNode();
+}

main/src/main/java/sd/protocol/SocketConnection.java

@@ -0,0 +1,198 @@
+package sd.protocol; 
+
+import java.io.Closeable;
+import java.io.DataInputStream;
+import java.io.DataOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.net.ConnectException;
+import java.net.Socket;
+import java.net.SocketTimeoutException;
+import java.net.UnknownHostException;
+import java.util.concurrent.TimeUnit;
+
+import sd.serialization.MessageSerializer;
+import sd.serialization.SerializationException;
+import sd.serialization.SerializerFactory;
+
+
+/**
+ * Wrapper class that simplifies communication via Sockets.
+ * Includes connection retry logic for robustness.
+ */
+public class SocketConnection implements Closeable {
+
+    private final Socket socket;
+    private final OutputStream outputStream;
+    private final InputStream inputStream;
+    private final MessageSerializer serializer;
+
+    // --- Configuration for Retry Logic ---
+    /** Maximum number of connection attempts. */
+    private static final int MAX_RETRIES = 5; 
+    /** Delay between retry attempts in milliseconds. */
+    private static final long RETRY_DELAY_MS = 1000; 
+
+    /**
+     * Constructor for the "Client" (who initiates the connection).
+     * Tries to connect to a process that is already listening (Server).
+     * Includes retry logic in case of initial connection failure.
+     *
+     * @param host The host address (e.g., "localhost" from your simulation.properties)
+     * @param port The port (e.g., 8001 from your simulation.properties)
+     * @throws IOException If connection fails after all retries.
+     * @throws UnknownHostException If the host is not found (this error usually doesn't need retry).
+     * @throws InterruptedException If the thread is interrupted while waiting between retries.
+     */
+    public SocketConnection(String host, int port) throws IOException, UnknownHostException, InterruptedException {
+        Socket tempSocket = null;
+        IOException lastException = null;
+
+        System.out.printf("[SocketConnection] Attempting to connect to %s:%d...%n", host, port);
+
+        // --- Retry Loop ---
+        for (int attempt = 1; attempt <= MAX_RETRIES; attempt++) {
+            try {
+                // Try to establish the connection
+                tempSocket = new Socket(host, port);
+
+                // If successful, break out of the retry loop
+                System.out.printf("[SocketConnection] Connected successfully on attempt %d.%n", attempt);
+                lastException = null; // Clear last error on success
+                break;
+
+            } catch (ConnectException | SocketTimeoutException e) {
+                // These are common errors indicating the server might not be ready.
+                lastException = e;
+                System.out.printf("[SocketConnection] Attempt %d/%d failed: %s. Retrying in %d ms...%n",
+                        attempt, MAX_RETRIES, e.getMessage(), RETRY_DELAY_MS);
+
+                if (attempt < MAX_RETRIES) {
+                    // Wait before the next attempt
+                    TimeUnit.MILLISECONDS.sleep(RETRY_DELAY_MS);
+                }
+            } catch (IOException e) {
+                // Other IOExceptions might be more permanent, but we retry anyway.
+                 lastException = e;
+                 System.out.printf("[SocketConnection] Attempt %d/%d failed with IOException: %s. Retrying in %d ms...%n",
+                        attempt, MAX_RETRIES, e.getMessage(), RETRY_DELAY_MS);
+                 if (attempt < MAX_RETRIES) {
+                     TimeUnit.MILLISECONDS.sleep(RETRY_DELAY_MS);
+                 }
+            }
+        } // --- End of Retry Loop ---
+
+        // If after all retries tempSocket is still null, it means connection failed permanently.
+        if (tempSocket == null) {
+            System.err.printf("[SocketConnection] Failed to connect to %s:%d after %d attempts.%n", host, port, MAX_RETRIES);
+            if (lastException != null) {
+                 throw lastException; // Throw the last exception encountered
+            } else {
+                 // Should not happen if loop ran, but as a fallback
+                 throw new IOException("Failed to connect after " + MAX_RETRIES + " attempts, reason unknown.");
+            }
+        }
+
+        // If connection was successful, assign to final variable and create streams
+        this.socket = tempSocket;
+          
+        this.outputStream = socket.getOutputStream();
+        this.inputStream = socket.getInputStream();
+        this.serializer = SerializerFactory.createDefault();
+
+    }
+
+
+    /**
+     * Constructor for the "Server" (who accepts the connection).
+     * Receives a Socket that has already been accepted by a ServerSocket.
+     * No retry logic needed here as the connection is already established.
+     *
+     * @param acceptedSocket The Socket returned by serverSocket.accept().
+     * @throws IOException If stream creation fails.
+     */
+    public SocketConnection(Socket acceptedSocket) throws IOException {
+        this.socket = acceptedSocket;
+        this.outputStream = socket.getOutputStream();
+        this.inputStream = socket.getInputStream();
+        this.serializer = SerializerFactory.createDefault();
+        
+    }
+
+    /**
+     * Sends (serializes) a MessageProtocol object over the socket.
+     *
+     * @param message The "envelope" (which contains the Vehicle) to be sent.
+     * @throws IOException If writing to the stream fails or socket is not connected.
+     */
+    public synchronized void sendMessage(MessageProtocol message) throws IOException {
+   if (socket == null || !socket.isConnected()) {
+            throw new IOException("Socket is not connected");
+        }
+
+        try {
+            // Serializa para bytes JSON
+            byte[] data = serializer.serialize(message);
+            
+            // Write 4-byte length prefix
+            DataOutputStream dataOut = new DataOutputStream(outputStream);
+            dataOut.writeInt(data.length);
+            dataOut.write(data);
+            dataOut.flush();
+            
+        } catch (SerializationException e) {
+            throw new IOException("Failed to serialize message", e);
+        }
+    }
+
+    /**
+     * Tries to read (deserialize) a MessageProtocol object from the socket.
+     *
+     * @return The "envelope" (MessageProtocol) that was received.
+     * @throws IOException If the connection is lost, the stream is corrupted, or socket is not connected.
+     * @throws ClassNotFoundException If the received object is unknown.
+     */
+    public MessageProtocol receiveMessage() throws IOException, ClassNotFoundException {
+       if (socket == null || !socket.isConnected()) {
+            throw new IOException("Socket is not connected");
+        }
+
+        try {
+            // Lê um prefixo de 4 bytes - indicador de tamanho
+            DataInputStream dataIn = new DataInputStream(inputStream);
+            int length = dataIn.readInt();
+            
+            if (length <= 0 || length > 10_000_000) { // Sanity check (10MB max)
+                throw new IOException("Invalid message length: " + length);
+            }
+            
+            // Ler dados da mensagem
+            byte[] data = new byte[length];
+            dataIn.readFully(data);
+            
+            // Deserialize do JSON - use concrete Message class, not interface
+            return serializer.deserialize(data, sd.model.Message.class);
+            
+        } catch (SerializationException e) {
+            throw new IOException("Failed to deserialize message", e);
+        }
+    }
+
+    /**
+     * Closes the socket and all streams (Input and Output).
+     */
+    @Override
+    public void close() throws IOException {
+        if (inputStream != null) inputStream.close();
+        if (outputStream != null) outputStream.close();
+        if (socket != null) socket.close();
+    }
+
+    /**
+     * @return true if the socket is still connected and not closed.
+     */
+    public boolean isConnected() {
+        return socket != null && socket.isConnected() && !socket.isClosed();
+    }
+}

main/src/main/java/sd/serialization/JsonMessageSerializer.java

@@ -0,0 +1,114 @@
+package sd.serialization;
+
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+import com.google.gson.JsonSyntaxException;
+
+import java.nio.charset.StandardCharsets;
+
+/**
+ * JSON-based implementation of {@link MessageSerializer} using Google's Gson library.
+ * 
+ * This serializer converts objects to JSON format for transmission, providing:
+ * - Human-readable message format (easy debugging)
+ * - Cross-platform compatibility
+ * - Smaller message sizes compared to Java native serialization
+ * - Better security (no code execution during deserialization)
+ * 
+ * The serializer is configured with pretty printing disabled by default for
+ * production use, but can be enabled for debugging purposes.
+ * 
+ * Thread-safety: This class is thread-safe as Gson instances are thread-safe.
+ * 
+ * @see MessageSerializer
+ */
+public class JsonMessageSerializer implements MessageSerializer {
+    
+    private final Gson gson;
+    private final boolean prettyPrint;
+    
+    /**
+     * Creates a new JSON serializer with default configuration (no pretty printing).
+     */
+    public JsonMessageSerializer() {
+        this(false);
+    }
+    
+    /**
+     * Creates a new JSON serializer with optional pretty printing.
+     * 
+     * @param prettyPrint If true, JSON output will be formatted with indentation
+     */
+    public JsonMessageSerializer(boolean prettyPrint) {
+        this.prettyPrint = prettyPrint;
+        GsonBuilder builder = new GsonBuilder();
+        
+        if (prettyPrint) {
+            builder.setPrettyPrinting();
+        }
+        
+        // Register custom type adapters here if needed
+        // builder.registerTypeAdapter(Vehicle.class, new VehicleAdapter());
+        
+        this.gson = builder.create();
+    }
+    
+    @Override
+    public byte[] serialize(Object object) throws SerializationException {
+        if (object == null) {
+            throw new IllegalArgumentException("Cannot serialize null object");
+        }
+        
+        try {
+            String json = gson.toJson(object);
+            return json.getBytes(StandardCharsets.UTF_8);
+        } catch (Exception e) {
+            throw new SerializationException(
+                "Failed to serialize object of type " + object.getClass().getName(), e);
+        }
+    }
+    
+    @Override
+    public <T> T deserialize(byte[] data, Class<T> clazz) throws SerializationException {
+        if (data == null) {
+            throw new IllegalArgumentException("Cannot deserialize null data");
+        }
+        if (clazz == null) {
+            throw new IllegalArgumentException("Class type cannot be null");
+        }
+        
+        try {
+            String json = new String(data, StandardCharsets.UTF_8);
+            return gson.fromJson(json, clazz);
+        } catch (JsonSyntaxException e) {
+            throw new SerializationException(
+                "Failed to parse JSON for type " + clazz.getName(), e);
+        } catch (Exception e) {
+            throw new SerializationException(
+                "Failed to deserialize object of type " + clazz.getName(), e);
+        }
+    }
+    
+    @Override
+    public String getName() {
+        return "JSON (Gson)";
+    }
+    
+    /**
+     * Returns the underlying Gson instance for advanced usage.
+     * 
+     * @return The Gson instance
+     */
+    public Gson getGson() {
+        return gson;
+    }
+    
+    /**
+     * Checks if pretty printing is enabled.
+     * 
+     * @return true if pretty printing is enabled
+     */
+    public boolean isPrettyPrint() {
+        return prettyPrint;
+    }
+}

main/src/main/java/sd/serialization/MessageSerializer.java

@@ -0,0 +1,48 @@
+package sd.serialization;
+
+/**
+ * Interface for serializing and deserializing objects for network transmission.
+ * 
+ * This interface provides a common abstraction for different serialization strategies
+ * allowing the system to switch between implementations without changing the communication layer.
+ * 
+ * Implementations must ensure:
+ * - Thread-safety if used in concurrent contexts
+ * - Proper exception handling with meaningful error messages
+ * - Preservation of object state during round-trip serialization
+ * 
+ * @see JsonMessageSerializer
+ */
+public interface MessageSerializer {
+    
+    /**
+     * Serializes an object into a byte array for transmission.
+     * 
+     * @param object The object to serialize (must not be null)
+     * @return A byte array containing the serialized representation
+     * @throws SerializationException If serialization fails
+     * @throws IllegalArgumentException If object is null
+     */
+    byte[] serialize(Object object) throws SerializationException;
+    
+    /**
+     * Deserializes a byte array back into an object of the specified type.
+     * 
+     * @param <T> The expected type of the deserialized object
+     * @param data The byte array containing serialized data (must not be null)
+     * @param clazz The class of the expected object type (must not be null)
+     * @return The deserialized object
+     * @throws SerializationException If deserialization fails
+     * @throws IllegalArgumentException If data or clazz is null
+     */
+    <T> T deserialize(byte[] data, Class<T> clazz) throws SerializationException;
+    
+    /**
+     * Gets the name of this serialization strategy (e.g., "JSON", "Java Native").
+     * Useful for logging and debugging.
+     * 
+     * @return The serializer name
+     */
+    String getName();
+    
+}

main/src/main/java/sd/serialization/SerializationException.java

@@ -0,0 +1,41 @@
+package sd.serialization;
+
+/**
+ * Exception thrown when serialization or deserialization operations fail.
+ * 
+ * This exception wraps underlying errors (I/O exceptions, parsing errors, etc.)
+ * and provides context about what went wrong during the serialization process.
+ */
+public class SerializationException extends Exception {
+    
+    private static final long serialVersionUID = 1L; // Long(64bits) instead of int(32bits)
+    
+    /**
+     * Constructs a new serialization exception with the specified detail message.
+     * 
+     * @param message The detail message
+     */
+    public SerializationException(String message) {
+        super(message);
+    }
+    
+    /**
+     * Constructs a new serialization exception with the specified detail message
+     * and cause.
+     * 
+     * @param message The detail message
+     * @param cause The cause of this exception
+     */
+    public SerializationException(String message, Throwable cause) {
+        super(message, cause);
+    }
+    
+    /**
+     * Constructs a new serialization exception with the specified cause.
+     * 
+     * @param cause The cause of this exception
+     */
+    public SerializationException(Throwable cause) {
+        super(cause);
+    }
+}

main/src/main/java/sd/serialization/SerializerFactory.java

@@ -0,0 +1,66 @@
+package sd.serialization;
+
+/**
+ * Factory for creating {@link MessageSerializer} instances.
+ * 
+ * This factory provides a centralized way to create and configure JSON serializers
+ * using Gson, making it easy to configure serialization throughout the application.
+ * 
+ * The factory can be configured via system properties for easy deployment configuration.
+ * 
+ * Example usage:
+ * <pre>
+ * MessageSerializer serializer = SerializerFactory.createDefault();
+ * byte[] data = serializer.serialize(myObject);
+ * </pre>
+ */
+public class SerializerFactory {
+    
+    /**
+     * System property key for enabling pretty-print in JSON serialization.
+     * Set to "true" for debugging, "false" for production.
+     */
+    public static final String JSON_PRETTY_PRINT_PROPERTY = "sd.serialization.json.prettyPrint";
+    
+    // Default configuration
+    private static final boolean DEFAULT_JSON_PRETTY_PRINT = false;
+    
+    /**
+     * Private constructor to prevent instantiation.
+     */
+    private SerializerFactory() {
+        throw new UnsupportedOperationException("Factory class cannot be instantiated");
+    }
+    
+    /**
+     * Creates a JSON serializer based on system configuration.
+     * 
+     * Pretty-print is determined by checking the system property
+     * {@value #JSON_PRETTY_PRINT_PROPERTY}. If not set, defaults to false.
+     * 
+     * @return A configured JsonMessageSerializer instance
+     */
+    public static MessageSerializer createDefault() {
+        boolean prettyPrint = Boolean.getBoolean(JSON_PRETTY_PRINT_PROPERTY);
+        return new JsonMessageSerializer(prettyPrint);
+    }
+    
+    /**
+     * Creates a JSON serializer with default configuration (no pretty printing).
+     * 
+     * @return A JsonMessageSerializer instance
+     */
+    public static MessageSerializer createSerializer() {
+        return createSerializer(DEFAULT_JSON_PRETTY_PRINT);
+    }
+    
+    /**
+     * Creates a JSON serializer with specified pretty-print setting.
+     * 
+     * @param prettyPrint Whether to enable pretty printing
+     * @return A JsonMessageSerializer instance
+     */
+    public static MessageSerializer createSerializer(boolean prettyPrint) {
+        return new JsonMessageSerializer(prettyPrint);
+    }
+}

main/src/main/java/sd/util/RandomGenerator.java

@@ -4,44 +4,71 @@ import java.util.Random;
 
 /**
  * Utility class for generating random values used throughout the simulation.
- * 
- * Includes helpers for exponential distributions (for vehicle arrivals),
- * uniform randoms, and probability-based decisions.
+ * * Provides static methods for:
+ * - Generating exponentially distributed intervals (for Poisson processes).
+ * - Generating random integers and doubles in a range.
+ * - Making decisions based on probability.
+ * - Choosing random elements from an array.
+ * * It uses a single, static {@link Random} instance.
  */
 public class RandomGenerator {
 
+    /**
+     * The single, shared Random instance for the entire simulation.
+     */
     private static final Random random = new Random();
 
     /**
      * Returns a random time interval that follows an exponential distribution.
-     * 
-     * Useful for modeling inter-arrival times in a Poisson process.
+     * * This is a key component for modeling a Poisson process, where the
+     * *inter-arrival times* (time between events) are exponentially distributed.
+     * The formula used is the inverse transform sampling method:
+     * {@code Time = -ln(1 - U) / λ}
+     * where U is a uniform random number [0, 1) and λ (lambda) is the
+     * average arrival rate.
      *
-     * @param lambda the arrival rate (λ)
-     * @return the time interval until the next arrival
+     * @param lambda The average arrival rate (λ) (e.g., 0.5 vehicles per second).
+     * @return The time interval (in seconds) until the next arrival.
      */
     public static double generateExponentialInterval(double lambda) {
+        // Math.log is the natural logarithm (ln)
+        // random.nextDouble() returns a value in [0.0, 1.0)
         return Math.log(1 - random.nextDouble()) / -lambda;
     }
 
     /**
      * Returns a random integer between {@code min} and {@code max}, inclusive.
+     *
+     * @param min The minimum possible value.
+     * @param max The maximum possible value.
+     * @return A random integer in the range [min, max].
      */
     public static int generateRandomInt(int min, int max) {
+        // random.nextInt(N) returns a value from 0 to N-1
+        // (max - min + 1) is the total number of integers in the range
+        // + min offsets the range
         return random.nextInt(max - min + 1) + min;
     }
 
     /**
      * Returns a random double between {@code min} (inclusive) and {@code max} (exclusive).
+     *
+     * @param min The minimum possible value.
+     * @param max The maximum possible value.
+     * @return A random double in the range [min, max).
      */
     public static double generateRandomDouble(double min, double max) {
         return min + (max - min) * random.nextDouble();
     }
 
     /**
-     * Returns {@code true} with the given probability.
-     * 
-     * @param probability a value between 0.0 and 1.0
+     * Returns {@code true} with a given probability.
+     * * This is useful for making weighted decisions. For example,
+     * {@code occursWithProbability(0.3)} will return {@code true}
+     * approximately 30% of the time.
+     *
+     * @param probability A value between 0.0 (never) and 1.0 (always).
+     * @return {@code true} or {@code false}, based on the probability.
      */
     public static boolean occursWithProbability(double probability) {
         return random.nextDouble() < probability;
@@ -49,20 +76,28 @@ public class RandomGenerator {
 
     /**
      * Picks a random element from the given array.
-     * 
-     * @throws IllegalArgumentException if the array is empty
+     *
+     * @param <T> The generic type of the array.
+     * @param array The array to choose from.
+     * @return A randomly selected element from the array.
+     * @throws IllegalArgumentException if the array is null or empty.
      */
     public static <T> T chooseRandom(T[] array) {
-        if (array.length == 0) {
-            throw new IllegalArgumentException("Array cannot be empty.");
+        if (array == null || array.length == 0) {
+            throw new IllegalArgumentException("Array cannot be null or empty.");
         }
         return array[random.nextInt(array.length)];
     }
 
     /**
-     * Sets the random generator’s seed, allowing reproducible results.
+     * Sets the seed of the shared random number generator.
+     * This is extremely useful for debugging and testing, as it allows
+     * the simulation to be run multiple times with the *exact same*
+     * sequence of "random" events, making the results reproducible.
+     *
+     * @param seed The seed to use.
      */
     public static void setSeed(long seed) {
         random.setSeed(seed);
     }
-}
+}

main/src/main/java/sd/util/VehicleGenerator.java

@@ -0,0 +1,229 @@
+package sd.util;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+import sd.config.SimulationConfig;
+import sd.model.Vehicle;
+import sd.model.VehicleType;
+
+/**
+ * Generates vehicles for the simulation.
+ * * This class is responsible for two key tasks:
+ * 1.  Determining *when* the next vehicle should arrive, based on the
+ * arrival model (POISSON or FIXED) from the {@link SimulationConfig}.
+ * 2.  Creating a new {@link Vehicle} object with a randomly selected
+ * type (e.g., BIKE, LIGHT) and a randomly selected route.
+ * * Routes are predefined and organized by entry point (E1, E2, E3).
+ */
+public class VehicleGenerator {
+    
+    private final SimulationConfig config;
+    private final String arrivalModel;
+    private final double arrivalRate;      // Lambda (λ) for POISSON
+    private final double fixedInterval;    // Interval for FIXED
+    
+    // --- Predefined Routes ---
+    // These lists store all possible routes, grouped by where they start.
+    
+    /** Routes starting from entry point E1. */
+    private final List<RouteWithProbability> e1Routes;
+    /** Routes starting from entry point E2. */
+    private final List<RouteWithProbability> e2Routes;
+    /** Routes starting from entry point E3. */
+    private final List<RouteWithProbability> e3Routes;
+    
+    /**
+     * Constructs a new VehicleGenerator.
+     * It reads the necessary configuration and initializes the
+     * predefined routes.
+     *
+     * @param config The {@link SimulationConfig} object.
+     */
+    public VehicleGenerator(SimulationConfig config) {
+        this.config = config;
+        
+        // Cache configuration values for performance
+        this.arrivalModel = config.getArrivalModel();
+        this.arrivalRate = config.getArrivalRate();
+        this.fixedInterval = config.getFixedArrivalInterval();
+        
+        // Initialize route lists
+        this.e1Routes = new ArrayList<>();
+        this.e2Routes = new ArrayList<>();
+        this.e3Routes = new ArrayList<>();
+        initializePossibleRoutes();
+    }
+    
+    /**
+     * Defines all possible routes that vehicles can take, organized by
+     * their entry point (E1, E2, E3). Each route is given a
+     * probability, which determines how often it's chosen.
+     */
+    private void initializePossibleRoutes() {
+        // E1 routes (Starts at Cr1)
+        e1Routes.add(new RouteWithProbability(
+            Arrays.asList("Cr1", "Cr4", "Cr5", "S"), 0.34)); // E1 -> Cr1 -> Cr4 -> Cr5 -> Exit
+        e1Routes.add(new RouteWithProbability(
+            Arrays.asList("Cr1", "Cr2", "Cr5", "S"), 0.33)); // E1 -> Cr1 -> Cr2 -> Cr5 -> Exit
+        e1Routes.add(new RouteWithProbability(
+            Arrays.asList("Cr1", "Cr2", "Cr3", "S"), 0.33)); // E1 -> Cr1 -> Cr2 -> Cr3 -> Exit
+        
+        // E2 routes (Starts at Cr2)
+        e2Routes.add(new RouteWithProbability(
+            Arrays.asList("Cr2", "Cr5", "S"), 0.34)); // E2 -> Cr2 -> Cr5 -> Exit
+        e2Routes.add(new RouteWithProbability(
+            Arrays.asList("Cr2", "Cr3", "S"), 0.33)); // E2 -> Cr2 -> Cr3 -> Exit
+        e2Routes.add(new RouteWithProbability(
+            Arrays.asList("Cr2", "Cr1", "Cr4", "Cr5", "S"), 0.33)); // E2 -> Cr2 -> ... -> Exit
+        
+        // E3 routes (Starts at Cr3)
+        e3Routes.add(new RouteWithProbability(
+            Arrays.asList("Cr3", "S"), 0.34)); // E3 -> Cr3 -> Exit
+        e3Routes.add(new RouteWithProbability(
+            Arrays.asList("Cr3", "Cr2", "Cr5", "S"), 0.33)); // E3 -> Cr3 -> Cr2 -> Cr5 -> Exit
+        e3Routes.add(new RouteWithProbability(
+            Arrays.asList("Cr3", "Cr2", "Cr1", "Cr4", "Cr5", "S"), 0.33)); // E3 -> Cr3 -> ... -> Exit
+    }
+    
+    /**
+     * Calculates the *absolute* time of the next vehicle arrival
+     * based on the configured model.
+     * * @param currentTime The current simulation time, used as the base.
+     * @return The absolute time (e.g., {@code currentTime + interval})
+     * when the next vehicle should be generated.
+     */
+    public double getNextArrivalTime(double currentTime) {
+        if ("POISSON".equalsIgnoreCase(arrivalModel)) {
+            // For a Poisson process, the time *between* arrivals
+            // follows an exponential distribution.
+            double interval = RandomGenerator.generateExponentialInterval(arrivalRate);
+            return currentTime + interval;
+        } else {
+            // For a Fixed model, the interval is constant.
+            return currentTime + fixedInterval;
+        }
+    }
+    
+    /**
+     * Generates a new {@link Vehicle} object.
+     * This involves:
+     * 1. Selecting a random {@link VehicleType} based on probabilities.
+     * 2. Selecting a random route (entry point + path) based on probabilities.
+     *
+     * @param vehicleId The unique identifier for the new vehicle (e.g., "V123").
+     * @param entryTime The simulation time when this vehicle is being created.
+     * @return A new, configured {@link Vehicle} object.
+     */
+    public Vehicle generateVehicle(String vehicleId, double entryTime) {
+        VehicleType type = selectVehicleType();
+        List<String> route = selectRandomRoute();
+        
+        return new Vehicle(vehicleId, type, entryTime, route);
+    }
+    
+    /**
+     * Selects a {@link VehicleType} (BIKE, LIGHT, HEAVY) based on the
+     * probabilities defined in the {@link SimulationConfig}.
+     * * Uses a standard "cumulative probability" technique:
+     * 1. Get a random number {@code rand} from [0, 1).
+     * 2. If {@code rand < P(Bike)}, return BIKE.
+     * 3. Else if {@code rand < P(Bike) + P(Light)}, return LIGHT.
+     * 4. Else, return HEAVY.
+     *
+     * @return The selected {@link VehicleType}.
+     */
+    private VehicleType selectVehicleType() {
+        double bikeProbability = config.getBikeVehicleProbability();
+        double lightProbability = config.getLightVehicleProbability();
+        double heavyProbability = config.getHeavyVehicleProbability();
+        
+        // Normalize probabilities in case they don't sum to exactly 1.0
+        double total = bikeProbability + lightProbability + heavyProbability;
+        if (total == 0) return VehicleType.LIGHT; // Avoid division by zero
+        bikeProbability /= total;
+        lightProbability /= total;
+        
+        double rand = Math.random();
+        
+        if (rand < bikeProbability) {
+            return VehicleType.BIKE;
+        } else if (rand < bikeProbability + lightProbability) {
+            return VehicleType.LIGHT;
+        } else {
+            return VehicleType.HEAVY;
+        }
+    }
+    
+    /**
+     * Selects a random route for a new vehicle.
+     * This is a two-step process:
+     * 1. Randomly select an entry point (E1, E2, or E3) with equal probability.
+     * 2. From the chosen entry point's list of routes, select one
+     * based on their defined probabilities (using cumulative probability).
+     *
+     * @return A {@link List} of strings representing the chosen route (e.g., ["Cr1", "Cr4", "S"]).
+     */
+    private List<String> selectRandomRoute() {
+        // Step 1: Randomly select an entry point (E1, E2, or E3)
+        double entryRandom = Math.random();
+        List<RouteWithProbability> selectedRoutes;
+        
+        if (entryRandom < 0.333) {
+            selectedRoutes = e1Routes;
+        } else if (entryRandom < 0.666) {
+            selectedRoutes = e2Routes;
+        } else {
+            selectedRoutes = e3Routes;
+        }
+        
+        // Step 2: Select a route from the chosen list based on cumulative probabilities
+        double routeRand = Math.random();
+        double cumulative = 0.0;
+        
+        for (RouteWithProbability routeWithProb : selectedRoutes) {
+            cumulative += routeWithProb.probability;
+            if (routeRand <= cumulative) {
+                // Return a *copy* of the route to prevent modification
+                return new ArrayList<>(routeWithProb.route);
+            }
+        }
+        
+        // Fallback: This should only be reached if probabilities don't sum to 1
+        // (due to floating point errors)
+        return new ArrayList<>(selectedRoutes.get(0).route);
+    }
+    
+    /**
+     * @return A string providing information about the generator's configuration.
+     */
+    public String getInfo() {
+        int totalRoutes = e1Routes.size() + e2Routes.size() + e3Routes.size();
+        return String.format(
+            "VehicleGenerator{model=%s, rate=%.2f, interval=%.2f, routes=%d (E1:%d, E2:%d, E3:%d)}",
+            arrivalModel, arrivalRate, fixedInterval, totalRoutes,
+            e1Routes.size(), e2Routes.size(), e3Routes.size()
+        );
+    }
+    
+    /**
+     * A private inner "struct-like" class to hold a route (a List of strings)
+     * and its associated selection probability.
+     */
+    private static class RouteWithProbability {
+        final List<String> route;
+        final double probability;
+        
+        /**
+         * Constructs a new RouteWithProbability pair.
+         * @param route The list of intersection IDs.
+         * @param probability The probability (0.0 to 1.0) of this route
+         * being chosen *from its entry group*.
+         */
+        RouteWithProbability(List<String> route, double probability) {
+            this.route = route;
+            this.probability = probability;
+        }
+    }
+}

main/src/main/resources/dashboard.css

@@ -0,0 +1,142 @@
+/* Global Styles */
+.root {
+    -fx-background-color: #f4f7f6;
+    -fx-font-family: 'Segoe UI', sans-serif;
+}
+
+/* Header */
+.header {
+    -fx-background-color: linear-gradient(to right, #2c3e50, #4ca1af);
+    -fx-padding: 20;
+    -fx-effect: dropshadow(three-pass-box, rgba(0,0,0,0.2), 10, 0, 0, 5);
+}
+
+.header-title {
+    -fx-font-size: 28px;
+    -fx-font-weight: bold;
+    -fx-text-fill: white;
+}
+
+.header-subtitle {
+    -fx-font-size: 16px;
+    -fx-text-fill: #ecf0f1;
+}
+
+/* Buttons */
+.button-start {
+    -fx-background-color: #2ecc71;
+    -fx-text-fill: white;
+    -fx-font-weight: bold;
+    -fx-padding: 10 20;
+    -fx-background-radius: 5;
+    -fx-cursor: hand;
+    -fx-effect: dropshadow(three-pass-box, rgba(0,0,0,0.1), 5, 0, 0, 2);
+}
+
+.button-start:hover {
+    -fx-background-color: #27ae60;
+}
+
+.button-start:disabled {
+    -fx-background-color: #95a5a6;
+    -fx-opacity: 0.7;
+}
+
+.button-stop {
+    -fx-background-color: #e74c3c;
+    -fx-text-fill: white;
+    -fx-font-weight: bold;
+    -fx-padding: 10 20;
+    -fx-background-radius: 5;
+    -fx-cursor: hand;
+    -fx-effect: dropshadow(three-pass-box, rgba(0,0,0,0.1), 5, 0, 0, 2);
+}
+
+.button-stop:hover {
+    -fx-background-color: #c0392b;
+}
+
+.button-stop:disabled {
+    -fx-background-color: #95a5a6;
+    -fx-opacity: 0.7;
+}
+
+/* Cards / Panels */
+.card {
+    -fx-background-color: white;
+    -fx-background-radius: 8;
+    -fx-effect: dropshadow(three-pass-box, rgba(0,0,0,0.05), 10, 0, 0, 2);
+    -fx-padding: 0; 
+}
+
+.card-header {
+    -fx-background-color: #ecf0f1;
+    -fx-background-radius: 8 8 0 0;
+    -fx-padding: 10 15;
+    -fx-border-color: #bdc3c7;
+    -fx-border-width: 0 0 1 0;
+}
+
+.card-title {
+    -fx-font-size: 16px;
+    -fx-font-weight: bold;
+    -fx-text-fill: #2c3e50;
+}
+
+.card-content {
+    -fx-padding: 15;
+}
+
+/* Statistics Grid */
+.stat-label {
+    -fx-font-size: 14px;
+    -fx-text-fill: #7f8c8d;
+}
+
+.stat-value {
+    -fx-font-size: 20px;
+    -fx-font-weight: bold;
+    -fx-text-fill: #2980b9;
+}
+
+/* Tables */
+.table-view {
+    -fx-background-color: transparent;
+    -fx-border-color: transparent;
+}
+
+.table-view .column-header-background {
+    -fx-background-color: #ecf0f1;
+    -fx-border-color: #bdc3c7;
+    -fx-border-width: 0 0 1 0;
+}
+
+.table-view .column-header .label {
+    -fx-text-fill: #2c3e50;
+    -fx-font-weight: bold;
+}
+
+.table-row-cell {
+    -fx-background-color: white;
+    -fx-border-color: transparent;
+}
+
+.table-row-cell:odd {
+    -fx-background-color: #f9f9f9;
+}
+
+.table-row-cell:selected {
+    -fx-background-color: #3498db;
+    -fx-text-fill: white;
+}
+
+/* Footer */
+.footer {
+    -fx-background-color: #34495e;
+    -fx-padding: 10 20;
+}
+
+.footer-text {
+    -fx-text-fill: #ecf0f1;
+    -fx-font-size: 12px;
+}

main/src/main/resources/network_config.json

@@ -0,0 +1,43 @@
+{
+  "intersections": [
+    {
+      "id": "Cr1",
+      "lights": ["East", "South"],
+      "routes": {
+        "Cr2": "East",
+        "Cr4": "South"
+      }
+    },
+    {
+      "id": "Cr2",
+      "lights": ["West", "East", "South"],
+      "routes": {
+        "Cr1": "West",
+        "Cr3": "East",
+        "Cr5": "South"
+      }
+    },
+    {
+      "id": "Cr3",
+      "lights": ["West", "South"],
+      "routes": {
+        "Cr2": "West",
+        "S": "South"
+      }
+    },
+    {
+      "id": "Cr4",
+      "lights": ["East"],
+      "routes": {
+        "Cr5": "East"
+      }
+    },
+    {
+      "id": "Cr5",
+      "lights": ["East"],
+      "routes": {
+        "S": "East"
+      }
+    }
+  ]
+}

main/src/main/resources/simulation.properties

@@ -31,7 +31,7 @@ dashboard.port=9000
 # === SIMULATION CONFIGURATION ===
 
 # Total duration in seconds (3600 = 1 hour)
-simulation.duration=3600.0
+simulation.duration=3600
 
 # Vehicle arrival model: FIXED or POISSON
 simulation.arrival.model=POISSON
@@ -46,55 +46,34 @@ simulation.arrival.fixed.interval=2.0
 # === TRAFFIC LIGHT TIMINGS ===
 # Format: trafficlight.<intersection>.<direction>.<state>=<seconds>
 
-# Intersection 1
-trafficlight.Cr1.North.green=30.0
-trafficlight.Cr1.North.red=30.0
-trafficlight.Cr1.South.green=30.0
-trafficlight.Cr1.South.red=30.0
-trafficlight.Cr1.East.green=30.0
-trafficlight.Cr1.East.red=30.0
-trafficlight.Cr1.West.green=30.0
-trafficlight.Cr1.West.red=30.0
+# Intersection 1 (Entry point - balanced)
+trafficlight.Cr1.South.green=60.0
+trafficlight.Cr1.South.red=5.0
+trafficlight.Cr1.East.green=60.0
+trafficlight.Cr1.East.red=5.0
 
-# Intersection 2
-trafficlight.Cr2.North.green=25.0
-trafficlight.Cr2.North.red=35.0
-trafficlight.Cr2.South.green=25.0
-trafficlight.Cr2.South.red=35.0
-trafficlight.Cr2.East.green=35.0
-trafficlight.Cr2.East.red=25.0
-trafficlight.Cr2.West.green=35.0
-trafficlight.Cr2.West.red=25.0
+# Intersection 2 (Main hub - shorter cycles, favor East-West)
+trafficlight.Cr2.South.green=60.0
+trafficlight.Cr2.South.red=5.0
+trafficlight.Cr2.East.green=60.0
+trafficlight.Cr2.East.red=5.0
+trafficlight.Cr2.West.green=60.0
+trafficlight.Cr2.West.red=5.0
 
-# Intersection 3
-trafficlight.Cr3.North.green=30.0
-trafficlight.Cr3.North.red=30.0
-trafficlight.Cr3.South.green=30.0
-trafficlight.Cr3.South.red=30.0
-trafficlight.Cr3.East.green=30.0
-trafficlight.Cr3.East.red=30.0
-trafficlight.Cr3.West.green=30.0
-trafficlight.Cr3.West.red=30.0
+# Intersection 3 (Path to exit - favor East)
+trafficlight.Cr3.South.green=60.0
+trafficlight.Cr3.South.red=5.0
+trafficlight.Cr3.West.green=60.0
+trafficlight.Cr3.West.red=5.0
 
-# Intersection 4
-trafficlight.Cr4.North.green=30.0
-trafficlight.Cr4.North.red=30.0
-trafficlight.Cr4.South.green=30.0
-trafficlight.Cr4.South.red=30.0
-trafficlight.Cr4.East.green=30.0
-trafficlight.Cr4.East.red=30.0
-trafficlight.Cr4.West.green=30.0
-trafficlight.Cr4.West.red=30.0
+# Intersection 4 (Favor East toward Cr5)
+trafficlight.Cr4.East.green=60.0
+trafficlight.Cr4.East.red=5.0
+
+# Intersection 5 (Near exit - favor East)
+trafficlight.Cr5.East.green=60.0
+trafficlight.Cr5.East.red=5.0
 
-# Intersection 5
-trafficlight.Cr5.North.green=30.0
-trafficlight.Cr5.North.red=30.0
-trafficlight.Cr5.South.green=30.0
-trafficlight.Cr5.South.red=30.0
-trafficlight.Cr5.East.green=30.0
-trafficlight.Cr5.East.red=30.0
-trafficlight.Cr5.West.green=30.0
-trafficlight.Cr5.West.red=30.0
 
 # === VEHICLE CONFIGURATION ===
 # Probability distribution for vehicle types (must sum to 1.0)
@@ -103,11 +82,19 @@ vehicle.probability.light=0.6
 vehicle.probability.heavy=0.2
 
 # Average crossing times (in seconds)
-vehicle.crossing.time.bike=1.5
+vehicle.crossing.time.bike=1.0
 vehicle.crossing.time.light=2.0
 vehicle.crossing.time.heavy=4.0
 
+# Travel times between intersections (in seconds)
+# Base time for light vehicles (cars)
+vehicle.travel.time.base=1.0
+# Bike travel time = 0.5 × car travel time
+vehicle.travel.time.bike.multiplier=0.5
+# Heavy vehicle travel time = 4.0 x base travel time
+vehicle.travel.time.heavy.multiplier=4.0
+
 # === STATISTICS ===
 
 # Interval between dashboard updates (seconds)
-statistics.update.interval=10.0
+statistics.update.interval=0.1

main/src/test/java/IntersectionProcessTest.java

@@ -0,0 +1,527 @@
+import java.io.IOException;
+import java.net.InetSocketAddress;
+import java.net.Socket;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Arrays;
+
+import org.junit.jupiter.api.AfterEach;
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.Timeout;
+import org.junit.jupiter.api.io.TempDir;
+
+import sd.IntersectionProcess;
+import sd.model.MessageType;
+import sd.model.Vehicle;
+import sd.model.VehicleType;
+import sd.protocol.SocketConnection;
+
+/**
+ * Tests for IntersectionProcess - covers initialization, traffic lights,
+ * vehicle transfer and network stuff
+ */
+public class IntersectionProcessTest {
+
+    @TempDir
+    Path tempDir;
+
+    private Path configFile;
+    private IntersectionProcess intersectionProcess;
+
+    // setup test config before each test
+    @BeforeEach
+    public void setUp() throws IOException {
+        // create temp config file
+        configFile = tempDir.resolve("test-simulation.properties");
+
+        String configContent = """
+                # Test Simulation Configuration
+
+                # Intersection Network Configuration
+                intersection.Cr1.host=localhost
+                intersection.Cr1.port=18001
+                intersection.Cr2.host=localhost
+                intersection.Cr2.port=18002
+                intersection.Cr3.host=localhost
+                intersection.Cr3.port=18003
+                intersection.Cr4.host=localhost
+                intersection.Cr4.port=18004
+                intersection.Cr5.host=localhost
+                intersection.Cr5.port=18005
+
+                # Exit Configuration
+                exit.host=localhost
+                exit.port=18099
+
+                # Dashboard Configuration
+                dashboard.host=localhost
+                dashboard.port=18100
+
+                # Traffic Light Timing (seconds)
+                trafficLight.Cr1.East.greenTime=5.0
+                trafficLight.Cr1.East.redTime=5.0
+                trafficLight.Cr1.South.greenTime=5.0
+                trafficLight.Cr1.South.redTime=5.0
+                trafficLight.Cr1.West.greenTime=5.0
+                trafficLight.Cr1.West.redTime=5.0
+
+                trafficLight.Cr2.West.greenTime=4.0
+                trafficLight.Cr2.West.redTime=6.0
+                trafficLight.Cr2.East.greenTime=4.0
+                trafficLight.Cr2.East.redTime=6.0
+                trafficLight.Cr2.South.greenTime=4.0
+                trafficLight.Cr2.South.redTime=6.0
+
+                trafficLight.Cr3.West.greenTime=3.0
+                trafficLight.Cr3.West.redTime=7.0
+                trafficLight.Cr3.East.greenTime=3.0
+                trafficLight.Cr3.East.redTime=7.0
+
+                trafficLight.Cr4.East.greenTime=6.0
+                trafficLight.Cr4.East.redTime=4.0
+
+                trafficLight.Cr5.East.greenTime=5.0
+                trafficLight.Cr5.East.redTime=5.0
+
+                # Vehicle Crossing Times (seconds)
+                vehicle.bike.crossingTime=2.0
+                vehicle.light.crossingTime=3.0
+                vehicle.heavy.crossingTime=5.0
+                """;
+
+        Files.writeString(configFile, configContent);
+    }
+
+    @AfterEach
+    public void tearDown() {
+        if (intersectionProcess != null) {
+            try {
+                // Only shutdown if still running
+                intersectionProcess.shutdown();
+            } catch (Exception e) {
+                System.err.println("Error in tearDown: " + e.getMessage());
+            } finally {
+                intersectionProcess = null;
+            }
+        }
+    }
+
+    // ==================== Initialization Tests ====================
+
+    @Test
+    public void testConstructor_Success() throws IOException {
+        intersectionProcess = new IntersectionProcess("Cr1", configFile.toString());
+        assertNotNull(intersectionProcess);
+    }
+
+    @Test
+    public void testConstructor_InvalidConfig() {
+        Exception exception = assertThrows(IOException.class, () -> {
+            new IntersectionProcess("Cr1", "non-existent-config.properties");
+        });
+        assertNotNull(exception);
+    }
+
+    @Test
+    public void testInitialize_Cr1() throws IOException {
+        intersectionProcess = new IntersectionProcess("Cr1", configFile.toString());
+        assertDoesNotThrow(() -> intersectionProcess.initialize());
+    }
+
+    @Test
+    public void testInitialize_Cr2() throws IOException {
+        intersectionProcess = new IntersectionProcess("Cr2", configFile.toString());
+        assertDoesNotThrow(() -> intersectionProcess.initialize());
+    }
+
+    @Test
+    public void testInitialize_Cr3() throws IOException {
+        intersectionProcess = new IntersectionProcess("Cr3", configFile.toString());
+        assertDoesNotThrow(() -> intersectionProcess.initialize());
+    }
+
+    @Test
+    public void testInitialize_Cr4() throws IOException {
+        intersectionProcess = new IntersectionProcess("Cr4", configFile.toString());
+        assertDoesNotThrow(() -> intersectionProcess.initialize());
+    }
+
+    @Test
+    public void testInitialize_Cr5() throws IOException {
+        intersectionProcess = new IntersectionProcess("Cr5", configFile.toString());
+        assertDoesNotThrow(() -> intersectionProcess.initialize());
+    }
+
+    // traffic light creation tests
+
+    @Test
+    public void testTrafficLightCreation_Cr1_HasCorrectDirections() throws IOException {
+        intersectionProcess = new IntersectionProcess("Cr1", configFile.toString());
+        intersectionProcess.initialize();
+
+        // cant access private fields but initialization succeds
+        assertNotNull(intersectionProcess);
+    }
+
+    @Test
+    public void testTrafficLightCreation_Cr3_HasCorrectDirections() throws IOException {
+        intersectionProcess = new IntersectionProcess("Cr3", configFile.toString());
+        intersectionProcess.initialize();
+
+        // Cr3 has west and south only
+        assertNotNull(intersectionProcess);
+    }
+
+    @Test
+    public void testTrafficLightCreation_Cr4_HasSingleDirection() throws IOException {
+        intersectionProcess = new IntersectionProcess("Cr4", configFile.toString());
+        intersectionProcess.initialize();
+
+        // Cr4 only has east direction
+        assertNotNull(intersectionProcess);
+    }
+
+    // server startup tests
+
+    @Test
+    @Timeout(5)
+    public void testServerStart_BindsToCorrectPort() throws IOException, InterruptedException {
+        intersectionProcess = new IntersectionProcess("Cr1", configFile.toString());
+        intersectionProcess.initialize();
+
+        // start server in separate thread
+        Thread serverThread = new Thread(() -> {
+            try {
+                intersectionProcess.start();
+            } catch (IOException e) {
+                // expected on shutdown
+            }
+        });
+        serverThread.start();
+
+        // Wait for server to actually start with retries
+        boolean serverReady = false;
+        for (int i = 0; i < 20; i++) {
+            Thread.sleep(100);
+            try (Socket testSocket = new Socket()) {
+                testSocket.connect(new java.net.InetSocketAddress("localhost", 18001), 500);
+                serverReady = true;
+                break;
+            } catch (IOException e) {
+                // Server not ready yet, continue waiting
+            }
+        }
+
+        assertTrue(serverReady, "Server should start and bind to port 18001");
+
+        // Shutdown immediately after confirming server is running
+        intersectionProcess.shutdown();
+        serverThread.join(2000);
+    }
+
+    @Test
+    @Timeout(5)
+    public void testServerStart_MultipleIntersections() throws IOException, InterruptedException {
+        // test 2 intersections on diferent ports
+        IntersectionProcess cr1 = new IntersectionProcess("Cr1", configFile.toString());
+        IntersectionProcess cr2 = new IntersectionProcess("Cr2", configFile.toString());
+
+        cr1.initialize();
+        cr2.initialize();
+
+        Thread thread1 = new Thread(() -> {
+            try {
+                cr1.start();
+            } catch (IOException e) {
+            }
+        });
+
+        Thread thread2 = new Thread(() -> {
+            try {
+                cr2.start();
+            } catch (IOException e) {
+            }
+        });
+
+        thread1.start();
+        thread2.start();
+
+        Thread.sleep(500);
+
+        // check both are running
+        try (Socket socket1 = new Socket("localhost", 18001);
+                Socket socket2 = new Socket("localhost", 18002)) {
+            assertTrue(socket1.isConnected());
+            assertTrue(socket2.isConnected());
+        }
+
+        cr1.shutdown();
+        cr2.shutdown();
+        thread1.join(2000);
+        thread2.join(2000);
+    }
+
+    // vehicle transfer tests
+
+    @Test
+    @Timeout(10)
+    public void testVehicleTransfer_ReceiveVehicle() throws IOException, InterruptedException {
+        // setup reciever intersection
+        intersectionProcess = new IntersectionProcess("Cr2", configFile.toString());
+        intersectionProcess.initialize();
+
+        Thread serverThread = new Thread(() -> {
+            try {
+                intersectionProcess.start();
+            } catch (IOException e) {
+            }
+        });
+        serverThread.start();
+
+        Thread.sleep(500);
+
+        try {
+            // create test vehicle - FIXED: use 4-parameter constructor
+            java.util.List<String> route = Arrays.asList("Cr2", "Cr3", "S");
+            Vehicle vehicle = new Vehicle("V001", VehicleType.LIGHT, 0.0, route);
+
+            // send vehicle from Cr1 to Cr2 - FIXED: use SocketConnection
+            try (Socket socket = new Socket("localhost", 18002);
+                    SocketConnection conn = new SocketConnection(socket)) {
+
+                TestVehicleMessage message = new TestVehicleMessage("Cr1", "Cr2", vehicle);
+                conn.sendMessage(message);
+
+                Thread.sleep(1000); // wait for processing
+            }
+        } finally {
+            intersectionProcess.shutdown();
+            serverThread.join(2000);
+        }
+    }
+
+    // routing config tests
+
+    @Test
+    public void testRoutingConfiguration_Cr1() throws IOException {
+        intersectionProcess = new IntersectionProcess("Cr1", configFile.toString());
+        intersectionProcess.initialize();
+
+        // indirect test - if init works routing should be ok
+        assertNotNull(intersectionProcess);
+    }
+
+    @Test
+    public void testRoutingConfiguration_Cr5() throws IOException {
+        intersectionProcess = new IntersectionProcess("Cr5", configFile.toString());
+        intersectionProcess.initialize();
+
+        // Cr5 routes to exit
+        assertNotNull(intersectionProcess);
+    }
+
+    // shutdown tests
+
+    @Test
+    @Timeout(5)
+    public void testShutdown_GracefulTermination() throws IOException, InterruptedException {
+        intersectionProcess = new IntersectionProcess("Cr1", configFile.toString());
+        intersectionProcess.initialize();
+
+        Thread serverThread = new Thread(() -> {
+            try {
+                intersectionProcess.start();
+            } catch (IOException e) {
+            }
+        });
+        serverThread.start();
+
+        Thread.sleep(500);
+
+        // shutdown should be fast
+        assertDoesNotThrow(() -> intersectionProcess.shutdown());
+
+        serverThread.join(2000);
+    }
+
+    @Test
+    @Timeout(5)
+    public void testShutdown_ClosesServerSocket() throws IOException, InterruptedException {
+        intersectionProcess = new IntersectionProcess("Cr1", configFile.toString());
+        intersectionProcess.initialize();
+
+        // Start server in separate thread
+        Thread serverThread = new Thread(() -> {
+            try {
+                intersectionProcess.start();
+            } catch (IOException e) {
+                // Expected on shutdown
+            }
+        });
+        serverThread.start();
+
+        // Wait for server to start
+        Thread.sleep(500);
+
+        // Shutdown
+        intersectionProcess.shutdown();
+        serverThread.join(2000);
+
+        // Give shutdown time to complete
+        Thread.sleep(200);
+
+        // Verify we cannot connect (server socket is closed)
+        boolean connectionFailed = false;
+        try (Socket testSocket = new Socket()) {
+            testSocket.connect(new InetSocketAddress("localhost", 18001), 500);
+        } catch (IOException e) {
+            connectionFailed = true; // Expected - server should be closed
+        }
+
+        assertTrue(connectionFailed, "Server socket should be closed after shutdown");
+    }
+
+    @Test
+    @Timeout(5)
+    public void testShutdown_StopsTrafficLightThreads() throws IOException, InterruptedException {
+        intersectionProcess = new IntersectionProcess("Cr1", configFile.toString());
+        intersectionProcess.initialize();
+
+        Thread serverThread = new Thread(() -> {
+            try {
+                intersectionProcess.start();
+            } catch (IOException e) {
+            }
+        });
+        serverThread.start();
+
+        Thread.sleep(500);
+
+        int threadCountBefore = Thread.activeCount();
+
+        intersectionProcess.shutdown();
+        serverThread.join(2000);
+
+        Thread.sleep(500); // wait for threads to die
+
+        // thread count should decrese (traffic light threads stop)
+        int threadCountAfter = Thread.activeCount();
+        assertTrue(threadCountAfter <= threadCountBefore);
+    }
+
+    // integration tests
+
+    @Test
+    @Timeout(15)
+    public void testIntegration_TwoIntersectionsVehicleTransfer() throws IOException, InterruptedException {
+        IntersectionProcess cr1 = null;
+        IntersectionProcess cr2 = null;
+        Thread thread1 = null;
+        Thread thread2 = null;
+
+        try {
+            // setup 2 intersections
+            cr1 = new IntersectionProcess("Cr1", configFile.toString());
+            cr2 = new IntersectionProcess("Cr2", configFile.toString());
+
+            cr1.initialize();
+            cr2.initialize();
+
+            // start both
+            final IntersectionProcess cr1Final = cr1;
+            thread1 = new Thread(() -> {
+                try {
+                    cr1Final.start();
+                } catch (IOException e) {
+                }
+            });
+
+            final IntersectionProcess cr2Final = cr2;
+            thread2 = new Thread(() -> {
+                try {
+                    cr2Final.start();
+                } catch (IOException e) {
+                }
+            });
+
+            thread1.start();
+            thread2.start();
+
+            Thread.sleep(1000); // wait for servers
+
+            // send vehicle to Cr1 that goes to Cr2 - FIXED: use 4-parameter constructor
+            java.util.List<String> route = Arrays.asList("Cr1", "Cr2", "S");
+            Vehicle vehicle = new Vehicle("V001", VehicleType.LIGHT, 0.0, route);
+
+            // FIXED: use SocketConnection
+            try (Socket socket = new Socket("localhost", 18001);
+                    SocketConnection conn = new SocketConnection(socket)) {
+
+                TestVehicleMessage message = new TestVehicleMessage("Entry", "Cr1", vehicle);
+                conn.sendMessage(message);
+
+                Thread.sleep(2000); // time for processing
+            }
+        } finally {
+            if (cr1 != null) {
+                cr1.shutdown();
+            }
+            if (cr2 != null) {
+                cr2.shutdown();
+            }
+            if (thread1 != null) {
+                thread1.join(2000);
+            }
+            if (thread2 != null) {
+                thread2.join(2000);
+            }
+        }
+    }
+
+    @Test
+    public void testMain_MissingArguments() {
+        // main needs intersection ID as argument
+        // cant test System.exit easily in modern java
+        assertTrue(true, "Main method expects intersection ID as first argument");
+    }
+
+    // helper class for testing vehicle messages
+    private static class TestVehicleMessage implements sd.protocol.MessageProtocol {
+        private static final long serialVersionUID = 1L;
+
+        private final String sourceNode;
+        private final String destinationNode;
+        private final Vehicle payload;
+
+        public TestVehicleMessage(String sourceNode, String destinationNode, Vehicle vehicle) {
+            this.sourceNode = sourceNode;
+            this.destinationNode = destinationNode;
+            this.payload = vehicle;
+        }
+
+        @Override
+        public MessageType getType() {
+            return MessageType.VEHICLE_TRANSFER;
+        }
+
+        @Override
+        public Object getPayload() {
+            return payload;
+        }
+
+        @Override
+        public String getSourceNode() {
+            return sourceNode;
+        }
+
+        @Override
+        public String getDestinationNode() {
+            return destinationNode;
+        }
+    }
+}

main/src/test/java/SimulationTest.java

@@ -0,0 +1,82 @@
+import java.io.IOException;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import org.junit.jupiter.api.Test;
+
+import sd.config.SimulationConfig;
+import sd.model.Intersection;
+import sd.model.TrafficLight;
+import sd.model.TrafficLightState;
+import sd.model.Vehicle;
+import sd.model.VehicleType;
+import sd.util.VehicleGenerator;
+
+/**
+ * Basic tests for the simulation components.
+ */
+class SimulationTest {
+
+    @Test
+    void testConfigurationLoading() throws IOException {
+        SimulationConfig config = new SimulationConfig("src/main/resources/simulation.properties");
+
+        assertEquals(60.0, config.getSimulationDuration());
+        assertEquals("POISSON", config.getArrivalModel());
+        assertEquals(0.5, config.getArrivalRate());
+        assertEquals(1.0, config.getStatisticsUpdateInterval());
+    }
+
+    @Test
+    void testVehicleGeneration() throws IOException {
+        SimulationConfig config = new SimulationConfig("src/main/resources/simulation.properties");
+        VehicleGenerator generator = new VehicleGenerator(config);
+
+        Vehicle vehicle = generator.generateVehicle("TEST1", 0.0);
+
+        assertNotNull(vehicle);
+        assertEquals("TEST1", vehicle.getId());
+        assertNotNull(vehicle.getType());
+        assertNotNull(vehicle.getRoute());
+        assertTrue(!vehicle.getRoute().isEmpty());
+    }
+
+    @Test
+    void testIntersectionVehicleQueue() {
+        Intersection intersection = new Intersection("TestCr");
+        TrafficLight light = new TrafficLight("TestCr-N", "North", 30.0, 30.0);
+
+        intersection.addTrafficLight(light);
+
+        Vehicle v1 = new Vehicle("V1", VehicleType.LIGHT, 0.0,
+                java.util.Arrays.asList("TestCr", "S"));
+
+        intersection.configureRoute("S", "North");
+
+        // Advance route to next destination
+        v1.advanceRoute();
+
+        intersection.receiveVehicle(v1);
+
+        assertEquals(1, intersection.getTotalQueueSize());
+        assertEquals(1, intersection.getTotalVehiclesReceived());
+    }
+
+    @Test
+    void testTrafficLightStateChange() {
+        TrafficLight light = new TrafficLight("Test-Light", "North", 30.0, 30.0);
+
+        assertEquals(TrafficLightState.RED, light.getState());
+
+        light.changeState(TrafficLightState.GREEN);
+        assertEquals(TrafficLightState.GREEN, light.getState());
+
+        light.changeState(TrafficLightState.RED);
+        assertEquals(TrafficLightState.RED, light.getState());
+    }
+
+    // Removed testSimulationEngineInitialization as SimulationEngine has been
+    // removed.
+
+}

main/src/test/java/TravelTimeTest.java

@@ -0,0 +1,159 @@
+import java.io.IOException;
+import java.net.ServerSocket;
+import java.net.Socket;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Arrays;
+import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.LinkedBlockingQueue;
+import java.util.concurrent.TimeUnit;
+
+import org.junit.jupiter.api.AfterEach;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.Timeout;
+import org.junit.jupiter.api.io.TempDir;
+
+import sd.IntersectionProcess;
+import sd.model.Message;
+import sd.model.MessageType;
+import sd.model.Vehicle;
+import sd.model.VehicleType;
+import sd.protocol.SocketConnection;
+
+public class TravelTimeTest {
+
+    @TempDir
+    Path tempDir;
+
+    private Path configFile;
+    private IntersectionProcess intersectionProcess;
+    private Thread serverThread;
+
+    @BeforeEach
+    public void setUp() throws IOException {
+        configFile = tempDir.resolve("test-simulation.properties");
+        String configContent = """
+                intersection.Cr1.host=localhost
+                intersection.Cr1.port=19001
+                intersection.Cr2.host=localhost
+                intersection.Cr2.port=19002
+
+                # Base travel time = 1.0s for testing
+                vehicle.travel.time.base=1.0
+                vehicle.travel.time.bike.multiplier=0.5
+                vehicle.travel.time.heavy.multiplier=4.0
+
+                # Dummy values for others
+                dashboard.host=localhost
+                dashboard.port=19100
+                exit.host=localhost
+                exit.port=19099
+                """;
+        Files.writeString(configFile, configContent);
+    }
+
+    @AfterEach
+    public void tearDown() {
+        if (intersectionProcess != null) {
+            intersectionProcess.shutdown();
+        }
+        if (serverThread != null) {
+            try {
+                serverThread.join(2000);
+            } catch (InterruptedException e) {
+                e.printStackTrace();
+            }
+        }
+    }
+
+    @Test
+    @Timeout(10)
+    public void testVariableTravelTimes() throws IOException, InterruptedException {
+        // Start Intersection Cr1
+        intersectionProcess = new IntersectionProcess("Cr1", configFile.toString());
+        // Mock network config for Cr1 to know about Cr2
+        // Since we can't easily inject network config without file, we rely on
+        // IntersectionProcess
+        // using the properties file we created. But wait, IntersectionProcess loads
+        // network_config.json
+        // from classpath. This might be an issue if we need custom routing.
+        // However, sendVehicleToNextDestination just looks up host/port from
+        // properties.
+        // We need to ensure getOrCreateConnection works.
+
+        // Let's manually inject the connection or just rely on properties.
+        // The properties file has intersection.Cr2.host/port, so it should work.
+
+        // Start a "fake" Cr2 server to receive the vehicle
+        BlockingQueue<Long> arrivalTimes = new LinkedBlockingQueue<>();
+        ServerSocket fakeCr2 = new ServerSocket(19002);
+        Thread cr2Thread = new Thread(() -> {
+            try {
+                Socket socket = fakeCr2.accept();
+                SocketConnection conn = new SocketConnection(socket);
+                while (!Thread.currentThread().isInterrupted()) {
+                    try {
+                        conn.receiveMessage();
+                        arrivalTimes.offer(System.currentTimeMillis());
+                    } catch (Exception e) {
+                        break;
+                    }
+                }
+            } catch (IOException e) {
+                // End
+            }
+        });
+        cr2Thread.start();
+
+        // Send vehicles from Cr1
+        // We need to call sendVehicleToNextDestination directly.
+        // But we need to initialize Cr1 first (at least the executor).
+        // We can't easily call initialize() because it tries to connect to dashboard
+        // etc.
+        // But the constructor initializes the executors!
+
+        // 1. Light Vehicle (Base = 1.0s)
+        Vehicle lightVehicle = new Vehicle("V_LIGHT", VehicleType.LIGHT, 0, Arrays.asList("Cr2"));
+        long startLight = System.currentTimeMillis();
+        intersectionProcess.sendVehicleToNextDestination(lightVehicle);
+
+        Long arrivalLight = arrivalTimes.poll(2000, TimeUnit.MILLISECONDS);
+        assertNotNull(arrivalLight, "Light vehicle should arrive");
+        long durationLight = arrivalLight - startLight;
+        System.out.println("Light Duration: " + durationLight + "ms");
+        assertTrue(durationLight >= 1000, "Light vehicle should take at least 1000ms");
+        assertTrue(durationLight < 1500, "Light vehicle should be close to 1000ms");
+
+        // 2. Bike (0.5 * 1.0 = 0.5s)
+        Vehicle bikeVehicle = new Vehicle("V_BIKE", VehicleType.BIKE, 0, Arrays.asList("Cr2"));
+        long startBike = System.currentTimeMillis();
+        intersectionProcess.sendVehicleToNextDestination(bikeVehicle);
+
+        Long arrivalBike = arrivalTimes.poll(2000, TimeUnit.MILLISECONDS);
+        assertNotNull(arrivalBike, "Bike should arrive");
+        long durationBike = arrivalBike - startBike;
+        System.out.println("Bike Duration: " + durationBike + "ms");
+        assertTrue(durationBike >= 500, "Bike should take at least 500ms");
+        assertTrue(durationBike < 1000, "Bike should be close to 500ms");
+
+        // 3. Heavy (4.0 * 1.0 = 4.0s)
+        Vehicle heavyVehicle = new Vehicle("V_HEAVY", VehicleType.HEAVY, 0, Arrays.asList("Cr2"));
+        long startHeavy = System.currentTimeMillis();
+        intersectionProcess.sendVehicleToNextDestination(heavyVehicle);
+
+        Long arrivalHeavy = arrivalTimes.poll(5000, TimeUnit.MILLISECONDS);
+        assertNotNull(arrivalHeavy, "Heavy vehicle should arrive");
+        long durationHeavy = arrivalHeavy - startHeavy;
+        System.out.println("Heavy Duration: " + durationHeavy + "ms");
+        assertTrue(durationHeavy >= 4000, "Heavy vehicle should take at least 4000ms");
+        assertTrue(durationHeavy < 4500, "Heavy vehicle should be close to 4000ms");
+
+        // Cleanup
+        fakeCr2.close();
+        cr2Thread.interrupt();
+    }
+}

main/src/test/java/sd/ExitNodeProcessTest.java

@@ -0,0 +1,327 @@
+package sd;
+
+import java.io.IOException;
+import java.net.Socket;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+
+import org.junit.jupiter.api.AfterEach;
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.Timeout;
+import org.junit.jupiter.api.io.TempDir;
+
+import sd.config.SimulationConfig;
+
+/**
+ * Testes unitários para a classe ExitNodeProcess.
+ * 
+ * Esta classe de testes verifica:
+ * - Construção e inicialização do processo
+ * - Criação e aceitação de conexões do servidor socket
+ * - Gestão do ciclo de vida (start/shutdown)
+ * - Processamento concorrente de múltiplas conexões
+ * - Impressão de estatísticas finais
+ * 
+ * Os testes utilizam configurações temporárias e portas dedicadas (19001)
+ * para evitar conflitos com outros testes ou processos em execução.
+ */
+public class ExitNodeProcessTest {
+
+    @TempDir
+    Path tempDir;
+
+    private Path configFile;
+    private ExitNodeProcess exitNodeProcess;
+    private Thread exitNodeThread;
+
+    /**
+     * Configura o ambiente de teste antes de cada teste.
+     * Cria um ficheiro de configuração temporário com as definições necessárias.
+     */
+    @BeforeEach
+    public void setUp() throws IOException {
+        configFile = tempDir.resolve("test-simulation.properties");
+        
+        String configContent = """
+                # Test Exit Node Configuration
+                
+                # Exit Configuration
+                exit.host=localhost
+                exit.port=19001
+                
+                # Dashboard Configuration (will not be running in tests)
+                dashboard.host=localhost
+                dashboard.port=19000
+                
+                # Vehicle Crossing Times
+                vehicle.bike.crossingTime=2.0
+                vehicle.light.crossingTime=3.0
+                vehicle.heavy.crossingTime=5.0
+                
+                # Simulation Duration
+                simulation.duration=60.0
+                """;
+        
+        Files.writeString(configFile, configContent);
+    }
+
+    /**
+     * Limpa os recursos após cada teste.
+     * Garante que o processo e threads são terminados corretamente.
+     */
+    @AfterEach
+    public void tearDown() {
+        if (exitNodeProcess != null) {
+            exitNodeProcess.shutdown();
+        }
+        if (exitNodeThread != null && exitNodeThread.isAlive()) {
+            exitNodeThread.interrupt();
+            try {
+                exitNodeThread.join(1000);
+            } catch (InterruptedException e) {
+                Thread.currentThread().interrupt();
+            }
+        }
+    }
+
+    /**
+     * Testa a construção bem-sucedida do ExitNodeProcess com configuração válida.
+     */
+    @Test
+    public void testConstructor_Success() throws IOException {
+        SimulationConfig config = new SimulationConfig(configFile.toString());
+        exitNodeProcess = new ExitNodeProcess(config);
+        assertNotNull(exitNodeProcess);
+    }
+
+    /**
+     * Testa que uma exceção é lançada quando a configuração é inválida.
+     */
+    @Test
+    public void testConstructor_InvalidConfig() {
+        Exception exception = assertThrows(IOException.class, () -> {
+            new SimulationConfig("non-existent-config.properties");
+        });
+        assertNotNull(exception);
+    }
+
+    /**
+     * Testa a inicialização sem dashboard disponível.
+     * Verifica que o processo continua a funcionar mesmo sem conexão ao dashboard.
+     */
+    @Test
+    public void testInitialize_WithoutDashboard() throws IOException {
+        SimulationConfig config = new SimulationConfig(configFile.toString());
+        exitNodeProcess = new ExitNodeProcess(config);
+        assertDoesNotThrow(() -> exitNodeProcess.initialize());
+    }
+
+    /**
+     * Testa que o servidor socket é criado corretamente na porta configurada.
+     * Verifica que é possível estabelecer uma conexão ao socket do servidor.
+     */
+    @Test
+    @Timeout(value = 3, unit = TimeUnit.SECONDS)
+    public void testStart_ServerSocketCreated() throws IOException {
+        SimulationConfig config = new SimulationConfig(configFile.toString());
+        exitNodeProcess = new ExitNodeProcess(config);
+        exitNodeProcess.initialize();
+        
+        CountDownLatch latch = new CountDownLatch(1);
+        
+        exitNodeThread = new Thread(() -> {
+            try {
+                latch.countDown();
+                exitNodeProcess.start();
+            } catch (IOException e) {
+                // expected when shutdown
+            }
+        });
+        
+        exitNodeThread.start();
+        
+        try {
+            assertTrue(latch.await(2, TimeUnit.SECONDS), "Exit node should start within timeout");
+            Thread.sleep(100);
+            
+            assertDoesNotThrow(() -> {
+                try (Socket testSocket = new Socket("localhost", 19001)) {
+                    assertTrue(testSocket.isConnected());
+                }
+            });
+        } catch (InterruptedException e) {
+            Thread.currentThread().interrupt();
+        }
+    }
+
+    /**
+     * Testa que o servidor aceita conexões de clientes.
+     */
+    @Test
+    @Timeout(value = 3, unit = TimeUnit.SECONDS)
+    public void testStart_AcceptsConnection() throws IOException, InterruptedException {
+        SimulationConfig config = new SimulationConfig(configFile.toString());
+        exitNodeProcess = new ExitNodeProcess(config);
+        exitNodeProcess.initialize();
+        
+        CountDownLatch latch = new CountDownLatch(1);
+        
+        exitNodeThread = new Thread(() -> {
+            try {
+                latch.countDown();
+                exitNodeProcess.start();
+            } catch (IOException e) {
+                // expected
+            }
+        });
+        
+        exitNodeThread.start();
+        
+        assertTrue(latch.await(2, TimeUnit.SECONDS));
+        Thread.sleep(200);
+        
+        assertDoesNotThrow(() -> {
+            try (Socket socket = new Socket("localhost", 19001)) {
+                assertTrue(socket.isConnected());
+            }
+        });
+    }
+
+    /**
+     * Testa múltiplas inicializações e encerramentos do processo.
+     * Verifica que o processo pode ser iniciado e parado múltiplas vezes,
+     * permitindo reutilização da porta.
+     */
+    @Test
+    @Timeout(value = 3, unit = TimeUnit.SECONDS)
+    public void testMultipleStartStop() throws IOException, InterruptedException {
+        SimulationConfig config = new SimulationConfig(configFile.toString());
+        exitNodeProcess = new ExitNodeProcess(config);
+        exitNodeProcess.initialize();
+        
+        CountDownLatch latch = new CountDownLatch(1);
+        
+        exitNodeThread = new Thread(() -> {
+            try {
+                latch.countDown();
+                exitNodeProcess.start();
+            } catch (IOException e) {
+                // expected
+            }
+        });
+        
+        exitNodeThread.start();
+        assertTrue(latch.await(2, TimeUnit.SECONDS));
+        Thread.sleep(100);
+        
+        exitNodeProcess.shutdown();
+        Thread.sleep(100);
+        
+        assertDoesNotThrow(() -> {
+            SimulationConfig config2 = new SimulationConfig(configFile.toString());
+            ExitNodeProcess exitNode2 = new ExitNodeProcess(config2);
+            exitNode2.initialize();
+            exitNode2.shutdown();
+        });
+    }
+
+    /**
+     * Testa que o shutdown fecha corretamente o servidor socket.
+     * Após o shutdown, novas conexões ao socket devem falhar.
+     */
+    @Test
+    @Timeout(value = 3, unit = TimeUnit.SECONDS)
+    public void testShutdown_ClosesServerSocket() throws IOException, InterruptedException {
+        SimulationConfig config = new SimulationConfig(configFile.toString());
+        exitNodeProcess = new ExitNodeProcess(config);
+        exitNodeProcess.initialize();
+        
+        CountDownLatch startLatch = new CountDownLatch(1);
+        
+        exitNodeThread = new Thread(() -> {
+            try {
+                startLatch.countDown();
+                exitNodeProcess.start();
+            } catch (IOException e) {
+                // expected
+            }
+        });
+        
+        exitNodeThread.start();
+        assertTrue(startLatch.await(2, TimeUnit.SECONDS));
+        Thread.sleep(200);
+        
+        exitNodeProcess.shutdown();
+        Thread.sleep(200);
+        
+        assertThrows(IOException.class, () -> {
+            Socket socket = new Socket("localhost", 19001);
+            socket.close();
+        });
+    }
+
+    /**
+     * Testa que as estatísticas finais são impressas corretamente durante o shutdown.
+     * Verifica que o método não lança exceções mesmo sem dados processados.
+     */
+    @Test
+    public void testPrintFinalStatistics() throws IOException {
+        SimulationConfig config = new SimulationConfig(configFile.toString());
+        exitNodeProcess = new ExitNodeProcess(config);
+        exitNodeProcess.initialize();
+        
+        assertDoesNotThrow(() -> exitNodeProcess.shutdown());
+    }
+
+    /**
+     * Testa o processamento de múltiplas conexões concorrentes.
+     * Verifica que o servidor consegue lidar com vários clientes simultaneamente
+     * usando o pool de threads.
+     */
+    @Test
+    @Timeout(value = 3, unit = TimeUnit.SECONDS)
+    public void testMultipleConcurrentConnections() throws IOException, InterruptedException {
+        SimulationConfig config = new SimulationConfig(configFile.toString());
+        exitNodeProcess = new ExitNodeProcess(config);
+        exitNodeProcess.initialize();
+        
+        CountDownLatch latch = new CountDownLatch(1);
+        
+        exitNodeThread = new Thread(() -> {
+            try {
+                latch.countDown();
+                exitNodeProcess.start();
+            } catch (IOException e) {
+                // expected
+            }
+        });
+        
+        exitNodeThread.start();
+        assertTrue(latch.await(2, TimeUnit.SECONDS));
+        Thread.sleep(200);
+        
+        Thread[] clients = new Thread[3];
+        for (int i = 0; i < 3; i++) {
+            clients[i] = new Thread(() -> {
+                try (Socket socket = new Socket("localhost", 19001)) {
+                    assertTrue(socket.isConnected());
+                    Thread.sleep(100);
+                } catch (IOException | InterruptedException e) {
+                    // ignore
+                }
+            });
+            clients[i].start();
+        }
+        
+        for (Thread client : clients) {
+            client.join(1000);
+        }
+    }
+}

main/src/test/java/sd/TrafficLightCoordinationTest.java

@@ -0,0 +1,207 @@
+package sd;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import org.junit.jupiter.api.AfterEach;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import sd.model.TrafficLight;
+import sd.model.TrafficLightState;
+
+/**
+ * Test class to verify traffic light coordination within an intersection.
+ * Ensures that only ONE traffic light can be GREEN at any given time.
+ */
+public class TrafficLightCoordinationTest {
+
+    private IntersectionProcess intersectionProcess;
+
+    @BeforeEach
+    public void setUp() throws IOException {
+        // Create an intersection with multiple traffic lights
+        intersectionProcess = new IntersectionProcess("Cr2", "src/main/resources/simulation.properties");
+        intersectionProcess.initialize();
+    }
+
+    @AfterEach
+    public void tearDown() throws InterruptedException {
+        if (intersectionProcess != null) {
+            intersectionProcess.shutdown();
+        }
+    }
+
+    /**
+     * Test that verifies mutual exclusion between traffic lights.
+     * Monitors all traffic lights for 10 seconds and ensures that
+     * at most ONE light is GREEN at any point in time.
+     */
+    @Test
+    public void testOnlyOneGreenLightAtATime() throws InterruptedException {
+        System.out.println("\n=== Testing Traffic Light Mutual Exclusion ===");
+
+        // Start the intersection
+        Thread intersectionThread = new Thread(() -> {
+            try {
+                intersectionProcess.start();
+            } catch (IOException e) {
+                e.printStackTrace();
+            }
+        });
+        intersectionThread.start();
+
+        // Monitor traffic lights for violations
+        AtomicInteger maxGreenSimultaneously = new AtomicInteger(0);
+        AtomicInteger violationCount = new AtomicInteger(0);
+        List<String> violations = new ArrayList<>();
+
+        // Monitor for 10 seconds
+        long endTime = System.currentTimeMillis() + 10000;
+
+        while (System.currentTimeMillis() < endTime) {
+            int greenCount = 0;
+            StringBuilder currentState = new StringBuilder("States: ");
+
+            for (TrafficLight light : intersectionProcess.getIntersection().getTrafficLights()) {
+                TrafficLightState state = light.getState();
+                currentState.append(light.getDirection()).append("=").append(state).append(" ");
+
+                if (state == TrafficLightState.GREEN) {
+                    greenCount++;
+                }
+            }
+
+            // Update maximum simultaneous green lights
+            if (greenCount > maxGreenSimultaneously.get()) {
+                maxGreenSimultaneously.set(greenCount);
+            }
+
+            // Check for violations (more than one green)
+            if (greenCount > 1) {
+                violationCount.incrementAndGet();
+                String violation = String.format("[VIOLATION] %d lights GREEN simultaneously: %s",
+                        greenCount, currentState.toString());
+                violations.add(violation);
+                System.err.println(violation);
+            }
+
+            Thread.sleep(50); // Check every 50ms
+        }
+
+        System.out.println("\n=== Test Results ===");
+        System.out.println("Maximum simultaneous GREEN lights: " + maxGreenSimultaneously.get());
+        System.out.println("Total violations detected: " + violationCount.get());
+
+        if (!violations.isEmpty()) {
+            System.err.println("\nViolation details:");
+            violations.forEach(System.err::println);
+        }
+
+        // Assert that we never had more than one green light
+        assertEquals(0, violationCount.get(),
+                "Traffic light coordination violated! Multiple lights were GREEN simultaneously.");
+        assertTrue(maxGreenSimultaneously.get() <= 1,
+                "At most ONE light should be GREEN at any time. Found: " + maxGreenSimultaneously.get());
+
+        System.out.println("\nTraffic light coordination working correctly!");
+    }
+
+    /**
+     * Test that verifies all traffic lights get a chance to be GREEN.
+     * Ensures fairness in the coordination mechanism.
+     */
+    @Test
+    public void testAllLightsGetGreenTime() throws InterruptedException {
+        System.out.println("\n=== Testing Traffic Light Fairness ===");
+
+        // Start the intersection
+        Thread intersectionThread = new Thread(() -> {
+            try {
+                intersectionProcess.start();
+            } catch (IOException e) {
+                e.printStackTrace();
+            }
+        });
+        intersectionThread.start();
+
+        // Track which lights have been green
+        List<TrafficLight> lights = intersectionProcess.getIntersection().getTrafficLights();
+        boolean[] hasBeenGreen = new boolean[lights.size()];
+
+        // Monitor for 10 seconds (enough time for all lights to cycle: 18+18+12 = 48s)
+        long endTime = System.currentTimeMillis() + 10000;
+
+        while (System.currentTimeMillis() < endTime) {
+            for (int i = 0; i < lights.size(); i++) {
+                if (lights.get(i).getState() == TrafficLightState.GREEN) {
+                    hasBeenGreen[i] = true;
+                    System.out.println("✓ " + lights.get(i).getDirection() + " has been GREEN");
+                }
+            }
+            Thread.sleep(100);
+        }
+
+        // Check if all lights got green time
+        int greenCount = 0;
+        System.out.println("\n=== Fairness Results ===");
+        for (int i = 0; i < lights.size(); i++) {
+            String status = hasBeenGreen[i] ? "✓ YES" : "✗ NO";
+            System.out.println(lights.get(i).getDirection() + " got GREEN time: " + status);
+            if (hasBeenGreen[i])
+                greenCount++;
+        }
+
+        assertTrue(greenCount > 0, "At least one light should have been GREEN during the test");
+        System.out.println("\n" + greenCount + "/" + lights.size() + " lights were GREEN during test period");
+    }
+
+    /**
+     * Test that verifies the state transitions are consistent.
+     */
+    @Test
+    public void testStateTransitionsAreConsistent() throws InterruptedException {
+        System.out.println("\n=== Testing State Transition Consistency ===");
+
+        Thread intersectionThread = new Thread(() -> {
+            try {
+                intersectionProcess.start();
+            } catch (IOException e) {
+                e.printStackTrace();
+            }
+        });
+        intersectionThread.start();
+
+        List<TrafficLight> lights = intersectionProcess.getIntersection().getTrafficLights();
+        TrafficLightState[] previousStates = new TrafficLightState[lights.size()];
+
+        // Initialize previous states
+        for (int i = 0; i < lights.size(); i++) {
+            previousStates[i] = lights.get(i).getState();
+        }
+
+        int transitionCount = 0;
+        long endTime = System.currentTimeMillis() + 8000;
+
+        while (System.currentTimeMillis() < endTime) {
+            for (int i = 0; i < lights.size(); i++) {
+                TrafficLightState currentState = lights.get(i).getState();
+
+                if (currentState != previousStates[i]) {
+                    transitionCount++;
+                    System.out.println(lights.get(i).getDirection() + " transitioned: " +
+                            previousStates[i] + " → " + currentState);
+                    previousStates[i] = currentState;
+                }
+            }
+            Thread.sleep(100);
+        }
+
+        System.out.println("\nTotal state transitions observed: " + transitionCount);
+        assertTrue(transitionCount > 0, "There should be state transitions during the test period");
+    }
+}

main/src/test/java/sd/coordinator/CoordinatorIntegrationTest.java

@@ -0,0 +1,302 @@
+package sd.coordinator;
+
+import java.io.DataInputStream;
+import java.io.IOException;
+import java.net.ServerSocket;
+import java.net.Socket;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.ConcurrentLinkedQueue;
+
+import org.junit.jupiter.api.AfterEach;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.Timeout;
+
+import sd.model.Message;
+import sd.model.MessageType;
+import sd.model.Vehicle;
+import sd.serialization.MessageSerializer;
+import sd.serialization.SerializerFactory;
+
+/**
+ * Integration tests for the Coordinator-side networking.
+ *
+ * What we’re checking here:
+ *  1. A SocketClient can actually connect to something listening
+ *  2. Messages go over the wire and can be deserialized
+ *  3. Vehicle payloads survive the trip
+ *  4. Shutdown messages can be broadcast to multiple intersections
+ *
+ * We do this by spinning up a tiny mock intersection server in-process.
+ */
+class CoordinatorIntegrationTest {
+    
+    private List<MockIntersectionServer> mockServers;
+    private static final int BASE_PORT = 9001; // keep clear of real ports
+    
+    @BeforeEach
+    void setUp() {
+        mockServers = new ArrayList<>();
+    }
+    
+    @AfterEach
+    void tearDown() {
+        // Stop all mock servers
+        for (MockIntersectionServer server : mockServers) {
+            server.stop();
+        }
+        mockServers.clear();
+    }
+    
+    /**
+     * Can the client open a TCP connection to our fake intersection?
+     */
+    @Test
+    @Timeout(5)
+    void testSocketClientConnection() throws IOException, InterruptedException {
+        MockIntersectionServer server = new MockIntersectionServer("Cr1", BASE_PORT);
+        server.start();
+        mockServers.add(server);
+        
+        // tiny pause to let the server bind
+        Thread.sleep(100);
+        
+        SocketClient client = new SocketClient("Cr1", "localhost", BASE_PORT);
+        client.connect();
+        
+        assertTrue(client.isConnected(), "Client should be connected to mock intersection");
+        
+        client.close();
+    }
+    
+    /**
+     * End-to-end: send a message, make sure the server actually receives it.
+     */
+    @Test
+    @Timeout(5)
+    void testMessageTransmission() throws Exception {
+        MockIntersectionServer server = new MockIntersectionServer("Cr1", BASE_PORT);
+        server.start();
+        mockServers.add(server);
+        
+        Thread.sleep(100);
+        
+        SocketClient client = new SocketClient("Cr1", "localhost", BASE_PORT);
+        client.connect();
+        
+        Message testMessage = new Message(
+            MessageType.VEHICLE_SPAWN,
+            "COORDINATOR",
+            "Cr1",
+            "Test payload"
+        );
+        
+        client.send(testMessage);
+        
+        // give the server a moment to read and deserialize
+        Thread.sleep(200);
+        
+        assertFalse(
+            server.getReceivedMessages().isEmpty(),
+            "Mock server should have received at least one message"
+        );
+        
+        Message receivedMsg = server.getReceivedMessages().poll();
+        assertNotNull(receivedMsg, "Server should have actually received a message");
+        assertEquals(MessageType.VEHICLE_SPAWN, receivedMsg.getType(), "Message type should match what we sent");
+        assertEquals("COORDINATOR", receivedMsg.getSenderId(), "Sender ID should be preserved");
+        assertEquals("Cr1", receivedMsg.getDestinationId(), "Destination ID should be preserved");
+        
+        client.close();
+    }
+    
+    /**
+     * Make sure vehicle payloads survive the trip and arrive non-null.
+     */
+    @Test
+    @Timeout(5)
+    void testVehicleSpawnMessage() throws Exception {
+        MockIntersectionServer server = new MockIntersectionServer("Cr1", BASE_PORT);
+        server.start();
+        mockServers.add(server);
+        
+        Thread.sleep(100);
+        
+        SocketClient client = new SocketClient("Cr1", "localhost", BASE_PORT);
+        client.connect();
+        
+        // fake a vehicle like the coordinator would send
+        List<String> route = List.of("Cr1", "Cr4", "Cr5", "S");
+        Vehicle vehicle = new Vehicle("V1", sd.model.VehicleType.LIGHT, 0.0, route);
+        
+        Message spawnMessage = new Message(
+            MessageType.VEHICLE_SPAWN,
+            "COORDINATOR",
+            "Cr1",
+            vehicle
+        );
+        
+        client.send(spawnMessage);
+        
+        Thread.sleep(200);
+        
+        Message receivedMsg = server.getReceivedMessages().poll();
+        assertNotNull(receivedMsg, "Mock server should receive the spawn message");
+        assertEquals(MessageType.VEHICLE_SPAWN, receivedMsg.getType(), "Message should be of type VEHICLE_SPAWN");
+        assertNotNull(receivedMsg.getPayload(), "Payload should not be null (vehicle must arrive)");
+        
+        client.close();
+    }
+    
+    /**
+     * Broadcast shutdown to multiple mock intersections and see if all of them get it.
+     */
+    @Test
+    @Timeout(5)
+    void testShutdownMessageBroadcast() throws Exception {
+        // Start a couple of fake intersections
+        for (int i = 1; i <= 3; i++) {
+            MockIntersectionServer server = new MockIntersectionServer("Cr" + i, BASE_PORT + i - 1);
+            server.start();
+            mockServers.add(server);
+        }
+        
+        Thread.sleep(200);
+        
+        // Connect to all of them
+        List<SocketClient> clients = new ArrayList<>();
+        for (int i = 1; i <= 3; i++) {
+            SocketClient client = new SocketClient("Cr" + i, "localhost", BASE_PORT + i - 1);
+            client.connect();
+            clients.add(client);
+        }
+        
+        Message shutdownMessage = new Message(
+            MessageType.SHUTDOWN,
+            "COORDINATOR",
+            "ALL",
+            "Simulation complete"
+        );
+        
+        for (SocketClient client : clients) {
+            client.send(shutdownMessage);
+        }
+        
+        Thread.sleep(200);
+        
+        for (MockIntersectionServer server : mockServers) {
+            assertFalse(
+                server.getReceivedMessages().isEmpty(),
+                "Server " + server.getIntersectionId() + " should have received the shutdown message"
+            );
+            
+            Message msg = server.getReceivedMessages().poll();
+            assertEquals(MessageType.SHUTDOWN, msg.getType(), "Server should receive a SHUTDOWN message");
+        }
+        
+        for (SocketClient client : clients) {
+            client.close();
+        }
+    }
+    
+    /**
+     * Tiny TCP server that pretends to be an intersection.
+     * It:
+     *  - listens on a port
+     *  - accepts connections
+     *  - reads length-prefixed messages
+     *  - deserializes them and stores them for the test to inspect
+     */
+    private static class MockIntersectionServer {
+        private final String intersectionId;
+        private final int port;
+        private ServerSocket serverSocket;
+        private Thread serverThread;
+        private volatile boolean running;
+        private final ConcurrentLinkedQueue<Message> receivedMessages;
+        private final MessageSerializer serializer;
+        
+        public MockIntersectionServer(String intersectionId, int port) {
+            this.intersectionId = intersectionId;
+            this.port = port;
+            this.receivedMessages = new ConcurrentLinkedQueue<>();
+            this.serializer = SerializerFactory.createDefault();
+            this.running = false;
+        }
+        
+        public void start() throws IOException {
+            serverSocket = new ServerSocket(port);
+            running = true;
+            
+            System.out.printf("Mock %s listening on port %d%n", intersectionId, port);
+            
+            serverThread = new Thread(() -> {
+                try {
+                    while (running) {
+                        Socket clientSocket = serverSocket.accept();
+                        handleClient(clientSocket);
+                    }
+                } catch (IOException e) {
+                    if (running) {
+                        System.err.println("Mock " + intersectionId + " server error: " + e.getMessage());
+                    }
+                }
+            }, "mock-" + intersectionId + "-listener");
+            
+            serverThread.start();
+        }
+        
+        private void handleClient(Socket clientSocket) {
+            new Thread(() -> {
+                try (DataInputStream input = new DataInputStream(clientSocket.getInputStream())) {
+                    while (running) {
+                        // Read length prefix (4 bytes, big-endian)
+                        int length = input.readInt();
+                        byte[] data = new byte[length];
+                        input.readFully(data);
+                        
+                        Message message = serializer.deserialize(data, Message.class);
+                        receivedMessages.offer(message);
+                        
+                        System.out.println("Mock " + intersectionId + " received: " + message.getType());
+                    }
+                } catch (IOException e) {
+                    if (running) {
+                        System.err.println("Mock " + intersectionId + " client handler error: " + e.getMessage());
+                    }
+                } catch (Exception e) {
+                    System.err.println("Mock " + intersectionId + " deserialization error: " + e.getMessage());
+                }
+            }, "mock-" + intersectionId + "-client").start();
+        }
+        
+        public void stop() {
+            running = false;
+            try {
+                if (serverSocket != null && !serverSocket.isClosed()) {
+                    serverSocket.close();
+                }
+                if (serverThread != null) {
+                    serverThread.interrupt();
+                    serverThread.join(1000);
+                }
+                System.out.printf("Mock %s stopped%n", intersectionId);
+            } catch (IOException | InterruptedException e) {
+                System.err.println("Error stopping mock server " + intersectionId + ": " + e.getMessage());
+            }
+        }
+        
+        public ConcurrentLinkedQueue<Message> getReceivedMessages() {
+            return receivedMessages;
+        }
+        
+        public String getIntersectionId() {
+            return intersectionId;
+        }
+    }
+}

main/src/test/java/sd/coordinator/CoordinatorProcessTest.java

@@ -0,0 +1,194 @@
+package sd.coordinator;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+
+import org.junit.jupiter.api.AfterEach;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import sd.config.SimulationConfig;
+import sd.model.Vehicle;
+import sd.util.VehicleGenerator;
+
+/**
+ * Tests for the Coordinator/vehicle-generation layer.
+ *
+ * What we’re checking here:
+ *  1. Coordinator can be created with a valid config
+ *  2. Vehicle arrival times are monotonic and sane
+ *  3. Vehicle IDs are created in the format we expect (V1, V2, ...)
+ *  4. Generated vehicles have proper routes (start at CrX, end at S)
+ *  5. Config actually has intersection info
+ *  6. Duration in config is not something crazy
+ */
+class CoordinatorProcessTest {
+    
+    private SimulationConfig config;
+    private static final String TEST_CONFIG = "src/main/resources/simulation.properties";
+    
+    @BeforeEach
+    void setUp() throws IOException {
+        config = new SimulationConfig(TEST_CONFIG);
+    }
+    
+    @AfterEach
+    void tearDown() {
+        config = null;
+    }
+    
+    /**
+     * Basic smoke test: can we build a coordinator with this config?
+     */
+    @Test
+    void testCoordinatorInitialization() {
+        CoordinatorProcess coordinator = new CoordinatorProcess(config);
+        assertNotNull(coordinator, "Coordinator should be created with a valid config");
+    }
+    
+    /**
+     * Make sure the VehicleGenerator is giving us increasing arrival times,
+     * i.e. time doesn’t go backwards and intervals look reasonable.
+     */
+    @Test
+    void testVehicleGenerationTiming() {
+        VehicleGenerator generator = new VehicleGenerator(config);
+        
+        double currentTime = 0.0;
+        List<Double> arrivalTimes = new ArrayList<>();
+        
+        // generate a small batch to inspect
+        for (int i = 0; i < 10; i++) {
+            double nextArrival = generator.getNextArrivalTime(currentTime);
+            arrivalTimes.add(nextArrival);
+            currentTime = nextArrival;
+        }
+        
+        // times should strictly increase
+        for (int i = 1; i < arrivalTimes.size(); i++) {
+            assertTrue(
+                arrivalTimes.get(i) > arrivalTimes.get(i - 1),
+                "Arrival times must increase — got " + arrivalTimes.get(i - 1) + " then " + arrivalTimes.get(i)
+            );
+        }
+        
+        // and they shouldn't be nonsense
+        for (double time : arrivalTimes) {
+            assertTrue(time >= 0, "Arrival time should not be negative (got " + time + ")");
+            assertTrue(time < 1000, "Arrival time looks suspiciously large: " + time);
+        }
+    }
+    
+    /**
+     * We generate V1..V5 manually and make sure the IDs are exactly those.
+     */
+    @Test
+    void testVehicleIdGeneration() {
+        VehicleGenerator generator = new VehicleGenerator(config);
+        
+        List<Vehicle> vehicles = new ArrayList<>();
+        for (int i = 1; i <= 5; i++) {
+            Vehicle v = generator.generateVehicle("V" + i, 0.0);
+            vehicles.add(v);
+            assertEquals("V" + i, v.getId(), "Vehicle ID should be 'V" + i + "' but got " + v.getId());
+        }
+        
+        // just to be safe, no duplicates in that small set
+        long distinctCount = vehicles.stream().map(Vehicle::getId).distinct().count();
+        assertEquals(5, distinctCount, "Vehicle IDs in this batch should all be unique");
+    }
+    
+    /**
+     * A generated vehicle should:
+     *  - have a non-empty route
+     *  - start in a known intersection (Cr1..Cr5)
+     *  - end in S (exit)
+     */
+    @Test
+    void testVehicleRouteValidity() {
+        VehicleGenerator generator = new VehicleGenerator(config);
+        
+        for (int i = 0; i < 20; i++) {
+            Vehicle vehicle = generator.generateVehicle("V" + i, 0.0);
+            
+            assertNotNull(vehicle.getRoute(), "Vehicle route should not be null");
+            assertFalse(vehicle.getRoute().isEmpty(), "Vehicle route should not be empty");
+            
+            String firstHop = vehicle.getRoute().get(0);
+            assertTrue(
+                firstHop.matches("Cr[1-5]"),
+                "First hop should be a valid intersection (Cr1..Cr5), got: " + firstHop
+            );
+            
+            String lastHop = vehicle.getRoute().get(vehicle.getRoute().size() - 1);
+            assertEquals("S", lastHop, "Last hop should be exit 'S' but got: " + lastHop);
+        }
+    }
+    
+    /**
+     * Whatever is in simulation.properties should give us a sane duration.
+     */
+    @Test
+    void testSimulationDuration() {
+        double duration = config.getSimulationDuration();
+        assertTrue(duration > 0, "Simulation duration must be positive");
+        assertTrue(duration >= 1.0, "Simulation should run at least 1 second (got " + duration + ")");
+        assertTrue(duration <= 86400.0, "Simulation should not run more than a day (got " + duration + ")");
+    }
+    
+    /**
+     * Check that the 5 intersections defined in the architecture
+     * actually exist in the config and have valid network data.
+     */
+    @Test
+    void testIntersectionConfiguration() {
+        String[] intersectionIds = {"Cr1", "Cr2", "Cr3", "Cr4", "Cr5"};
+        
+        for (String id : intersectionIds) {
+            String host = config.getIntersectionHost(id);
+            int port = config.getIntersectionPort(id);
+            
+            assertNotNull(host, "Host should not be null for " + id);
+            assertFalse(host.isEmpty(), "Host should not be empty for " + id);
+            assertTrue(port > 0, "Port should be > 0 for " + id + " (got " + port + ")");
+            assertTrue(port < 65536, "Port should be a valid TCP port for " + id + " (got " + port + ")");
+        }
+    }
+    
+    /**
+     * Quick sanity check: over a bunch of generated vehicles,
+     * we should eventually see the different vehicle types appear.
+     *
+     * Note: this is probabilistic, so we're not being super strict.
+     */
+    @Test
+    void testVehicleTypeDistribution() {
+        VehicleGenerator generator = new VehicleGenerator(config);
+        
+        boolean hasBike = false;
+        boolean hasLight = false;
+        boolean hasHeavy = false;
+        
+        // 50 is enough for a "we're probably fine" test
+        for (int i = 0; i < 50; i++) {
+            Vehicle vehicle = generator.generateVehicle("V" + i, 0.0);
+            
+            switch (vehicle.getType()) {
+                case BIKE -> hasBike = true;
+                case LIGHT -> hasLight = true;
+                case HEAVY -> hasHeavy = true;
+            }
+        }
+        
+        // at least one of them should have shown up — if not, RNG is cursed
+        assertTrue(
+            hasBike || hasLight || hasHeavy,
+            "Expected to see at least one vehicle type after 50 generations"
+        );
+    }
+}

main/src/test/java/sd/dashboard/DashboardTest.java

@@ -0,0 +1,164 @@
+package sd.dashboard;
+
+import org.junit.jupiter.api.AfterEach;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import sd.config.SimulationConfig;
+import sd.model.VehicleType;
+
+/**
+ * Unit tests for Dashboard Server components.
+ */
+class DashboardTest {
+    
+    private DashboardStatistics statistics;
+    
+    @BeforeEach
+    void setUp() {
+        statistics = new DashboardStatistics();
+    }
+    
+    @AfterEach
+    void tearDown() {
+        statistics = null;
+    }
+    
+    @Test
+    void testInitialStatistics() {
+        assertEquals(0, statistics.getTotalVehiclesGenerated(), 
+            "Initial vehicles generated should be 0");
+        assertEquals(0, statistics.getTotalVehiclesCompleted(), 
+            "Initial vehicles completed should be 0");
+        assertEquals(0.0, statistics.getAverageSystemTime(), 
+            "Initial average system time should be 0.0");
+        assertEquals(0.0, statistics.getAverageWaitingTime(), 
+            "Initial average waiting time should be 0.0");
+    }
+    
+    @Test
+    void testVehicleCounters() {
+        statistics.incrementVehiclesGenerated();
+        assertEquals(1, statistics.getTotalVehiclesGenerated());
+        
+        statistics.updateVehiclesGenerated(10);
+        assertEquals(10, statistics.getTotalVehiclesGenerated());
+        
+        statistics.incrementVehiclesCompleted();
+        assertEquals(1, statistics.getTotalVehiclesCompleted());
+    }
+    
+    @Test
+    void testAverageCalculations() {
+        // Add 3 completed vehicles with known times
+        statistics.updateVehiclesCompleted(3);
+        statistics.addSystemTime(3000); // 3000ms total
+        statistics.addWaitingTime(1500); // 1500ms total
+        
+        assertEquals(1000.0, statistics.getAverageSystemTime(), 0.01,
+            "Average system time should be 1000ms");
+        assertEquals(500.0, statistics.getAverageWaitingTime(), 0.01,
+            "Average waiting time should be 500ms");
+    }
+    
+    @Test
+    void testVehicleTypeStatistics() {
+        statistics.incrementVehicleType(VehicleType.LIGHT);
+        statistics.incrementVehicleType(VehicleType.LIGHT);
+        statistics.incrementVehicleType(VehicleType.HEAVY);
+        
+        assertEquals(2, statistics.getVehicleTypeCount(VehicleType.LIGHT));
+        assertEquals(1, statistics.getVehicleTypeCount(VehicleType.HEAVY));
+        assertEquals(0, statistics.getVehicleTypeCount(VehicleType.BIKE));
+    }
+    
+    @Test
+    void testIntersectionStatistics() {
+        statistics.updateIntersectionStats("Cr1", 10, 8, 2);
+        
+        DashboardStatistics.IntersectionStats stats = 
+            statistics.getIntersectionStats("Cr1");
+        
+        assertNotNull(stats, "Intersection stats should not be null");
+        assertEquals("Cr1", stats.getIntersectionId());
+        assertEquals(10, stats.getTotalArrivals());
+        assertEquals(8, stats.getTotalDepartures());
+        assertEquals(2, stats.getCurrentQueueSize());
+    }
+    
+    @Test
+    void testMultipleIntersections() {
+        statistics.updateIntersectionStats("Cr1", 10, 8, 2);
+        statistics.updateIntersectionStats("Cr2", 15, 12, 3);
+        statistics.updateIntersectionStats("Cr3", 5, 5, 0);
+        
+        assertEquals(3, statistics.getAllIntersectionStats().size(),
+            "Should have 3 intersections");
+    }
+    
+    @Test
+    void testStatsUpdatePayload() {
+        StatsUpdatePayload payload = new StatsUpdatePayload()
+            .setTotalVehiclesGenerated(50)
+            .setTotalVehiclesCompleted(20)
+            .setIntersectionArrivals(30)
+            .setIntersectionDepartures(25)
+            .setIntersectionQueueSize(5);
+        
+        assertEquals(50, payload.getTotalVehiclesGenerated());
+        assertEquals(20, payload.getTotalVehiclesCompleted());
+        assertEquals(30, payload.getIntersectionArrivals());
+        assertEquals(25, payload.getIntersectionDepartures());
+        assertEquals(5, payload.getIntersectionQueueSize());
+    }
+    
+    @Test
+    void testStatsMessage() {
+        StatsUpdatePayload payload = new StatsUpdatePayload()
+            .setIntersectionArrivals(10);
+        
+        StatsMessage message = new StatsMessage("Cr1", payload);
+        
+        assertEquals("Cr1", message.getSourceNode());
+        assertEquals("DashboardServer", message.getDestinationNode());
+        assertEquals(sd.model.MessageType.STATS_UPDATE, message.getType());
+        assertNotNull(message.getPayload());
+    }
+    
+    @Test
+    void testThreadSafety() throws InterruptedException {
+        // Test concurrent updates
+        Thread t1 = new Thread(() -> {
+            for (int i = 0; i < 100; i++) {
+                statistics.incrementVehiclesGenerated();
+            }
+        });
+        
+        Thread t2 = new Thread(() -> {
+            for (int i = 0; i < 100; i++) {
+                statistics.incrementVehiclesGenerated();
+            }
+        });
+        
+        t1.start();
+        t2.start();
+        t1.join();
+        t2.join();
+        
+        assertEquals(200, statistics.getTotalVehiclesGenerated(),
+            "Concurrent increments should total 200");
+    }
+    
+    @Test
+    void testDashboardServerCreation() throws Exception {
+        SimulationConfig config = new SimulationConfig("simulation.properties");
+        DashboardServer server = new DashboardServer(config);
+        
+        assertNotNull(server, "Server should be created successfully");
+        assertNotNull(server.getStatistics(), "Statistics should be initialized");
+        assertFalse(server.isRunning(), "Server should not be running initially");
+    }
+}

main/src/test/java/sd/serialization/SerializationTest.java

@@ -0,0 +1,140 @@
+package sd.serialization;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.DisplayName;
+import sd.model.Message;
+import sd.model.Vehicle;
+import sd.model.VehicleType;
+
+import java.util.Arrays;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+/**
+ * Test suite for JSON serialization.
+ * 
+ * Tests JSON serialization to ensure:
+ * - Correct serialization and deserialization
+ * - Data integrity during round-trip conversion
+ * - Proper error handling
+ */
+class SerializationTest {
+    
+    private MessageSerializer jsonSerializer = new JsonMessageSerializer();
+    
+    private Vehicle testVehicle = new Vehicle("V001", VehicleType.LIGHT, 10.5,
+            Arrays.asList("Cr1", "Cr2", "Cr5", "S"));
+    private Message testMessage = new Message(
+            sd.model.MessageType.VEHICLE_TRANSFER,
+            "Cr1",
+            "Cr2",
+            testVehicle
+    );
+    
+    
+    // ===== JSON Serialization Tests =====
+    
+    @Test
+    @DisplayName("JSON: Should serialize and deserialize Vehicle correctly")
+    void testJsonVehicleRoundTrip() throws SerializationException {
+        // Serialize
+        byte[] data = jsonSerializer.serialize(testVehicle);
+        assertNotNull(data);
+        assertTrue(data.length > 0);
+        
+        // Print JSON for inspection
+        System.out.println("JSON Vehicle:");
+        System.out.println(new String(data));
+        
+        // Deserialize
+        Vehicle deserialized = jsonSerializer.deserialize(data, Vehicle.class);
+        
+        // Verify
+        assertNotNull(deserialized);
+        assertEquals(testVehicle.getId(), deserialized.getId());
+        assertEquals(testVehicle.getType(), deserialized.getType());
+        assertEquals(testVehicle.getEntryTime(), deserialized.getEntryTime());
+        assertEquals(testVehicle.getRoute(), deserialized.getRoute());
+        assertEquals(testVehicle.getTotalWaitingTime(), deserialized.getTotalWaitingTime());
+        assertEquals(testVehicle.getTotalCrossingTime(), deserialized.getTotalCrossingTime());
+    }
+    
+    @Test
+    @DisplayName("JSON: Should serialize and deserialize Message correctly")
+    void testJsonMessageRoundTrip() throws SerializationException {
+        // Serialize
+        byte[] data = jsonSerializer.serialize(testMessage);
+        assertNotNull(data);
+        
+        // Print JSON for inspection
+        System.out.println("\nJSON Message:");
+        System.out.println(new String(data));
+        
+        // Deserialize
+        Message deserialized = jsonSerializer.deserialize(data, Message.class);
+        
+        // Verify
+        assertNotNull(deserialized);
+        assertEquals(testMessage.getType(), deserialized.getType());
+        assertEquals(testMessage.getSenderId(), deserialized.getSenderId());
+        assertEquals(testMessage.getDestinationId(), deserialized.getDestinationId());
+    }
+    
+    @Test
+    @DisplayName("JSON: Should throw exception on null object")
+    void testJsonSerializeNull() {
+        assertThrows(IllegalArgumentException.class, () -> {
+            jsonSerializer.serialize(null);
+        });
+    }
+    
+    @Test
+    @DisplayName("JSON: Should throw exception on null data")
+    void testJsonDeserializeNull() {
+        assertThrows(IllegalArgumentException.class, () -> {
+            jsonSerializer.deserialize(null, Vehicle.class);
+        });
+    }
+    
+    @Test
+    @DisplayName("JSON: Should throw exception on invalid JSON")
+    void testJsonDeserializeInvalid() {
+        byte[] invalidData = "{ invalid json }".getBytes();
+        assertThrows(SerializationException.class, () -> {
+            jsonSerializer.deserialize(invalidData, Vehicle.class);
+        });
+    }
+    
+    @Test
+    @DisplayName("JSON: Should preserve data integrity for complex objects")
+    void testDataIntegrity() throws SerializationException {
+        // Create a more complex vehicle
+        Vehicle vehicle = new Vehicle("V999", VehicleType.HEAVY, 100.5,
+            Arrays.asList("Cr1", "Cr2", "Cr3", "Cr4", "Cr5", "S"));
+        vehicle.addWaitingTime(10.5);
+        vehicle.addWaitingTime(5.3);
+        vehicle.addCrossingTime(2.1);
+        vehicle.advanceRoute();
+        vehicle.advanceRoute();
+        
+        // Serialize and deserialize
+        byte[] jsonData = jsonSerializer.serialize(vehicle);
+        Vehicle deserialized = jsonSerializer.deserialize(jsonData, Vehicle.class);
+        
+        // Verify all fields match
+        assertEquals(vehicle.getId(), deserialized.getId());
+        assertEquals(vehicle.getType(), deserialized.getType());
+        assertEquals(vehicle.getTotalWaitingTime(), deserialized.getTotalWaitingTime());
+        assertEquals(vehicle.getCurrentRouteIndex(), deserialized.getCurrentRouteIndex());
+    }
+    
+    // ===== Factory Tests =====
+    
+    @Test
+    @DisplayName("Factory: Should create JSON serializer by default")
+    void testFactoryDefault() {
+        MessageSerializer serializer = SerializerFactory.createDefault();
+        assertNotNull(serializer);
+        assertEquals("JSON (Gson)", serializer.getName());
+    }
+}

main/start.sh

@@ -0,0 +1,60 @@
+#!/bin/bash
+# Distributed Traffic Simulation Startup Script
+
+# kill java
+echo "-> Cleaning up existing processes..."
+pkill -9 java 2>/dev/null
+sleep 2
+
+# build
+echo "-> Building project..."
+cd "$(dirname "$0")"
+mvn package -DskipTests -q
+if [ $? -ne 0 ]; then
+    echo "XXX Build failed! XXX"
+    exit 1
+fi
+echo "-> Build complete"
+echo ""
+
+# start gui
+echo "-> Starting JavaFX Dashboard..."
+mvn javafx:run &
+DASHBOARD_PID=$!
+sleep 3
+
+# acho que é assim idk
+echo "-> Starting 5 Intersection processes..."
+for id in Cr1 Cr2 Cr3 Cr4 Cr5; do
+    java -cp target/classes:target/main-1.0-SNAPSHOT.jar sd.IntersectionProcess $id > /tmp/$(echo $id | tr '[:upper:]' '[:lower:]').log 2>&1 &
+    echo "[SUCCESS] Started $id"
+done
+sleep 2
+
+# exit
+echo "-> Starting Exit Node..."
+java -cp target/classes:target/main-1.0-SNAPSHOT.jar sd.ExitNodeProcess > /tmp/exit.log 2>&1 &
+sleep 1
+
+# coordinator
+echo "-> Starting Coordinator..."
+java -cp target/classes:target/main-1.0-SNAPSHOT.jar sd.coordinator.CoordinatorProcess > /tmp/coordinator.log 2>&1 &
+sleep 1
+
+echo ""
+echo "-> All processes started!"
+echo ""
+echo "-> System Status:"
+ps aux | grep "java.*sd\." | grep -v grep | wc -l | xargs -I {} echo "   {} Java processes running"
+echo ""
+echo "   IMPORTANT: Keep the JavaFX Dashboard window OPEN for 60+ seconds"
+echo "   to see live updates! The simulation runs for 60 seconds."
+echo ""
+echo "-> Logs available at:"
+echo "   Dashboard: Check JavaFX window (live updates)"
+echo "   Intersections: /tmp/cr*.log"
+echo "   Exit Node: /tmp/exit.log"
+echo "   Coordinator: /tmp/coordinator.log"
+echo ""
+echo "-> To stop all processes: pkill -9 java"
+echo ""