small fixes + debug

testing

.github/workflows/maven.yml

@@ -1,8 +1,9 @@
 name: Java CI with Maven
 
 on:
+  workflow_dispatch:
   push:
-    branches: [ "main" ]
+    branches: [ "dev", "cleanup" ]
     tags:
       - 'v*.*.*'
   pull_request:
@@ -11,51 +12,93 @@ on:
 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]
-    if: startsWith(github.ref, 'refs/tags/')
+    needs: [build, build-windows]
+    if: startsWith(github.ref, 'refs/tags/') || github.event_name == 'workflow_dispatch'
     permissions:
       contents: write
-
     steps:
-    - name: Download built JAR
+    - 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:
-        files: main/target/*.jar
+        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

main/pom.xml

@@ -51,7 +51,7 @@
                 <artifactId>exec-maven-plugin</artifactId>
                 <version>3.1.0</version>
                 <configuration>
-                    <mainClass>sd.Entry</mainClass>
+                    <mainClass>sd.dashboard.Launcher</mainClass>
                 </configuration>
             </plugin>
             <!-- JavaFX Maven Plugin -->
@@ -60,7 +60,7 @@
                 <artifactId>javafx-maven-plugin</artifactId>
                 <version>0.0.8</version>
                 <configuration>
-                    <mainClass>sd.dashboard.DashboardUI</mainClass>
+                    <mainClass>sd.dashboard.Launcher</mainClass>
                 </configuration>
             </plugin>
             <plugin>
@@ -76,7 +76,7 @@
                         <configuration>
                             <transformers>
                                 <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
-                                    <mainClass>sd.Entry</mainClass>
+                                    <mainClass>sd.dashboard.Launcher</mainClass>
                                 </transformer>
                             </transformers>
                         </configuration>

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

@@ -1,94 +0,0 @@
-package sd;
-
-import java.io.IOException;
-
-import sd.config.SimulationConfig;
-import sd.engine.SimulationEngine;
-
-/**
- * Main entry point for the traffic simulation.
- * * This class is responsible for loading the simulation configuration,
- * initializing the {@link SimulationEngine}, and starting the simulation run.
- * It also prints initial configuration details and final execution time.
- */
-public class Entry {
-    
-    /**
-     * The default path to the simulation configuration file.
-     * This is used if no command-line arguments are provided.
-     */
-    private static final String DEFAULT_CONFIG_FILE = "src/main/resources/simulation.properties";
-    
-    /**
-     * The main method to start the simulation.
-     * * @param args Command-line arguments. If provided, args[0] is expected
-     * to be the path to a custom configuration file.
-     */
-    public static void main(String[] args) {
-        System.out.println("=".repeat(60));
-        System.out.println("TRAFFIC SIMULATION - DISCRETE EVENT SIMULATOR");
-        System.out.println("=".repeat(60));
-        
-        try {
-            // 1. Load configuration
-            String configFile = args.length > 0 ? args[0] : DEFAULT_CONFIG_FILE;
-            System.out.println("Loading configuration from: " + configFile);
-            
-            SimulationConfig config = new SimulationConfig(configFile);
-            
-            // 2. Display configuration
-            displayConfiguration(config);
-            
-            // 3. Create and initialize simulation engine
-            SimulationEngine engine = new SimulationEngine(config);
-            engine.initialize();
-            
-            System.out.println("\n" + "=".repeat(60));
-            
-            // 4. Run simulation
-            long startTime = System.currentTimeMillis();
-            engine.run();
-            long endTime = System.currentTimeMillis();
-            
-            // 5. Display execution time
-            double executionTime = (endTime - startTime) / 1000.0;
-            System.out.println("\nExecution time: " + String.format("%.2f", executionTime) + " seconds");
-            System.out.println("=".repeat(60));
-            
-        } catch (IOException e) {
-            System.err.println("Error loading configuration: " + e.getMessage());
-            e.printStackTrace();
-        } catch (Exception e) {
-            System.err.println("Error during simulation: " + e.getMessage());
-            e.printStackTrace();
-        }
-    }
-    
-    /**
-     * Displays the main configuration parameters to the console.
-     * This provides a summary of the simulation settings before it starts.
-     *
-     * @param config The {@link SimulationConfig} object containing the loaded settings.
-     */
-    private static void displayConfiguration(SimulationConfig config) {
-        System.out.println("\nSIMULATION CONFIGURATION:");
-        System.out.println("  Duration: " + config.getSimulationDuration() + " seconds");
-        System.out.println("  Arrival Model: " + config.getArrivalModel());
-        
-        if ("POISSON".equalsIgnoreCase(config.getArrivalModel())) {
-            System.out.println("  Arrival Rate (λ): " + config.getArrivalRate() + " vehicles/second");
-        } else {
-            System.out.println("  Fixed Interval: " + config.getFixedArrivalInterval() + " seconds");
-        }
-        
-        System.out.println("  Statistics Update Interval: " + config.getStatisticsUpdateInterval() + " seconds");
-        
-        System.out.println("\nVEHICLE TYPES:");
-        System.out.println("  Bike: " + (config.getBikeVehicleProbability() * 100) + "% " +
-                         "(crossing time: " + config.getBikeVehicleCrossingTime() + "s)");
-        System.out.println("  Light: " + (config.getLightVehicleProbability() * 100) + "% " +
-                         "(crossing time: " + config.getLightVehicleCrossingTime() + "s)");
-        System.out.println("  Heavy: " + (config.getHeavyVehicleProbability() * 100) + "% " +
-                         "(crossing time: " + config.getHeavyVehicleCrossingTime() + "s)");
-    }
-}

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

@@ -18,12 +18,13 @@ import sd.model.Vehicle;
 import sd.model.VehicleType;
 import sd.protocol.MessageProtocol;
 import sd.protocol.SocketConnection;
-import sd.serialization.SerializationException;
 
 /**
- * Processo responsável pelo nó de saída do sistema de simulação de tráfego distribuído.
+ * 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.
+ * 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
@@ -36,7 +37,10 @@ public class ExitNodeProcess {
     private ServerSocket serverSocket;
     private final ExecutorService connectionHandlerPool;
 
-    /** Flag para controlar a execução do processo (volatile para visibilidade entre threads) */
+    /**
+     * Flag para controlar a execução do processo (volatile para visibilidade entre
+     * threads)
+     */
     private volatile boolean running;
 
     /** Simulation start time (milliseconds) to calculate relative times */
@@ -99,10 +103,12 @@ public class ExitNodeProcess {
     /**
      * Constrói um novo processo de nó de saída.
      * 
-     * Inicializa todas as estruturas de dados necessárias para recolher estatísticas
+     * 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
+     * @param config Configuração da simulação contendo portas e endereços dos
+     *               serviços
      */
     public ExitNodeProcess(SimulationConfig config) {
         this.config = config;
@@ -159,7 +165,8 @@ public class ExitNodeProcess {
      * 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
+     * @throws IOException Se o socket não puder ser criado ou houver erro na
+     *                     aceitação
      */
     public void start() throws IOException {
         int port = config.getExitPort();
@@ -186,7 +193,8 @@ public class ExitNodeProcess {
      * 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.
+     * VEHICLE_TRANSFER. Cada mensagem representa um veículo que chegou ao nó de
+     * saída.
      * 
      * @param clientSocket Socket da ligação estabelecida com a interseção
      */
@@ -201,7 +209,7 @@ public class ExitNodeProcess {
                     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());
+                            " from " + message.getSourceNode());
 
                     if (message.getType() == MessageType.SIMULATION_START) {
                         // Coordinator sends start time - use it instead of our local start
@@ -214,7 +222,7 @@ public class ExitNodeProcess {
                         // Handle Gson LinkedHashMap
                         Vehicle vehicle;
                         if (payload instanceof com.google.gson.internal.LinkedTreeMap ||
-                            payload instanceof java.util.LinkedHashMap) {
+                                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 {
@@ -274,24 +282,12 @@ public class ExitNodeProcess {
         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);
+                vehicle.getId(), vehicle.getType(), systemTime, waitTime, crossingTime);
 
         // Send stats after every vehicle to ensure dashboard updates quickly
         sendStatsToDashboard();
     }
 
-    /**
-     * Obtém o tempo atual da simulação em segundos.
-     * 
-     * @return Tempo atual em segundos desde "epoch"
-     * 
-     * "Epoch" é um ponto de referência temporal Unix (1 de janeiro de 1970).
-     * Este método retorna os segundos decorridos desde esse momento.
-     */
-    private double getCurrentTime() {
-        return System.currentTimeMillis() / 1000.0;
-    }
-    
     /**
      * Envia as estatísticas para o dashboard.
      * 
@@ -312,8 +308,13 @@ public class ExitNodeProcess {
 
             // 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
+            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<>();
@@ -321,7 +322,7 @@ public class ExitNodeProcess {
 
             for (VehicleType type : VehicleType.values()) {
                 typeCounts.put(type, vehicleTypeCount.get(type));
-                typeWaitTimes.put(type, (long)(vehicleTypeWaitTime.get(type) * 1000.0)); // s -> ms
+                typeWaitTimes.put(type, (long) (vehicleTypeWaitTime.get(type) * 1000.0)); // s -> ms
             }
 
             payload.setVehicleTypeCounts(typeCounts);
@@ -329,17 +330,16 @@ public class ExitNodeProcess {
 
             // Send message
             Message message = new Message(
-                MessageType.STATS_UPDATE,
-                "ExitNode",
-                "Dashboard",
-                payload
-            );
+                    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);
+                    totalVehiclesReceived, avgWait);
 
         } catch (Exception e) {
             System.err.println("[Exit] Failed to send stats to dashboard: " + e.getMessage());
@@ -350,11 +350,11 @@ public class ExitNodeProcess {
      * 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;
+     * 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...");
@@ -418,7 +418,7 @@ public class ExitNodeProcess {
                 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);
+                        type, count, percentage, avgWait);
             }
         }
     }

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

@@ -4,9 +4,11 @@ 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;
@@ -46,6 +48,9 @@ public class IntersectionProcess {
 
     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.
 
@@ -64,10 +69,8 @@ public class IntersectionProcess {
     private volatile String currentGreenDirection;
 
     private SocketClient dashboardClient;
-    private long simulationStartMillis;
     private volatile int totalArrivals = 0;
     private volatile int totalDepartures = 0;
-    private long lastStatsUpdateTime;
 
     /**
      * Constructs a new IntersectionProcess.
@@ -83,8 +86,10 @@ public class IntersectionProcess {
         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();
+        this.trafficCoordinationLock = new ReentrantLock(true); // Fair lock to prevent starvation
         this.currentGreenDirection = null;
 
         System.out.println("=".repeat(60));
@@ -142,17 +147,16 @@ public class IntersectionProcess {
             int dashboardPort = config.getDashboardPort();
 
             System.out.println("[" + intersectionId + "] Connecting to dashboard at " +
-                dashboardHost + ":" + dashboardPort + "...");
+                    dashboardHost + ":" + dashboardPort + "...");
 
             dashboardClient = new SocketClient(intersectionId, dashboardHost, dashboardPort);
             dashboardClient.connect();
 
             System.out.println("[" + intersectionId + "] Connected to dashboard.");
-            lastStatsUpdateTime = System.currentTimeMillis();
 
         } catch (IOException e) {
             System.err.println("[" + intersectionId + "] Failed to connect to dashboard: " +
-                e.getMessage());
+                    e.getMessage());
             System.err.println("[" + intersectionId + "] Will continue without dashboard reporting.");
             dashboardClient = null;
         }
@@ -167,23 +171,12 @@ public class IntersectionProcess {
     private void createTrafficLights() {
         System.out.println("\n[" + intersectionId + "] Creating traffic lights...");
 
-        String[] directions = new String[0];
-        switch (intersectionId) {
-            case "Cr1":
-                directions = new String[] { "East", "South" };
-                break;
-            case "Cr2":
-                directions = new String[] { "West", "East", "South" };
-                break;
-            case "Cr3":
-                directions = new String[] { "West", "South" };
-                break;
-            case "Cr4":
-                directions = new String[] { "East" };
-                break;
-            case "Cr5":
-                directions = new String[] { "East" };
-                break;
+        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) {
@@ -202,36 +195,31 @@ public class IntersectionProcess {
         }
     }
 
+    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...");
 
-        switch (intersectionId) {
-            case "Cr1":
-                intersection.configureRoute("Cr2", "East");
-                intersection.configureRoute("Cr4", "South");
-                break;
+        SimulationConfig.IntersectionConfig intersectionConfig = getIntersectionConfig();
+        Map<String, String> routes = intersectionConfig.getRoutes();
 
-            case "Cr2":
-                intersection.configureRoute("Cr1", "West");
-                intersection.configureRoute("Cr3", "East");
-                intersection.configureRoute("Cr5", "South");
-                break;
-
-            case "Cr3":
-                intersection.configureRoute("Cr2", "West");
-                intersection.configureRoute("S", "South");
-                break;
-
-            case "Cr4":
-                intersection.configureRoute("Cr5", "East");
-                break;
-
-            case "Cr5":
-                intersection.configureRoute("S", "East");
-                break;
-
-            default:
-                System.err.println("  Error: unknown intersection ID: " + intersectionId);
+        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.");
@@ -284,32 +272,49 @@ public class IntersectionProcess {
     public void sendVehicleToNextDestination(Vehicle vehicle) {
         String nextDestination = vehicle.getCurrentDestination();
 
-        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 + "] Sent vehicle " + vehicle.getId() +
-                    " to " + nextDestination);
-
-            // Record departure for statistics
-            recordVehicleDeparture();
-
-            // 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());
+        // 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);
     }
 
     /**
@@ -381,6 +386,9 @@ public class IntersectionProcess {
         // 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
@@ -447,14 +455,13 @@ public class IntersectionProcess {
 
                     // Handle simulation start time synchronization
                     if (message.getType() == MessageType.SIMULATION_START) {
-                        simulationStartMillis = ((Number) message.getPayload()).longValue();
                         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) {
+                            message.getType() == MessageType.VEHICLE_SPAWN) {
                         // Cast payload to Vehicle - handle Gson deserialization
                         Vehicle vehicle;
                         Object payload = message.getPayload();
@@ -481,6 +488,12 @@ public class IntersectionProcess {
 
                         // 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) {
@@ -524,6 +537,9 @@ public class IntersectionProcess {
         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 {
@@ -540,6 +556,12 @@ public class IntersectionProcess {
         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 {
@@ -549,6 +571,12 @@ public class IntersectionProcess {
             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();
         }
@@ -589,7 +617,6 @@ public class IntersectionProcess {
      */
     public void recordVehicleArrival() {
         totalArrivals++;
-        checkAndSendStats();
     }
 
     /**
@@ -597,21 +624,6 @@ public class IntersectionProcess {
      */
     public void recordVehicleDeparture() {
         totalDepartures++;
-        checkAndSendStats();
-    }
-
-    /**
-     * Checks if it's time to send statistics to the dashboard and sends them if needed.
-     */
-    private void checkAndSendStats() {
-        long now = System.currentTimeMillis();
-        long elapsed = now - lastStatsUpdateTime;
-        
-        // Send stats every 5 seconds
-        if (elapsed >= 5000) {
-            sendStatsToDashboard();
-            lastStatsUpdateTime = now;
-        }
     }
 
     /**
@@ -625,68 +637,28 @@ public class IntersectionProcess {
         try {
             // Calculate current queue size
             int currentQueueSize = intersection.getTrafficLights().stream()
-                .mapToInt(TrafficLight::getQueueSize)
-                .sum();
+                    .mapToInt(TrafficLight::getQueueSize)
+                    .sum();
 
             StatsUpdatePayload payload = new StatsUpdatePayload()
-                .setIntersectionArrivals(totalArrivals)
-                .setIntersectionDepartures(totalDepartures)
-                .setIntersectionQueueSize(currentQueueSize);
+                    .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
-            );
+                    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);
+                    intersectionId, totalArrivals, totalDepartures, currentQueueSize);
 
         } catch (SerializationException | IOException e) {
             System.err.println("[" + intersectionId + "] Failed to send stats to dashboard: " + e.getMessage());
         }
     }
-
-    // --- Inner class for Vehicle Transfer Messages ---
-
-    /**
-     * Implementation of MessageProtocol for vehicle transfers between processes.
-     */
-    private static class VehicleTransferMessage implements MessageProtocol {
-        private static final long serialVersionUID = 1L;
-
-        private final String sourceNode;
-        private final String destinationNode;
-        private final Vehicle payload;
-
-        public VehicleTransferMessage(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/main/java/sd/config/SimulationConfig.java

@@ -3,8 +3,16 @@ 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. This class provides
@@ -17,59 +25,144 @@ public class SimulationConfig {
      * 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;
+        }
+    }
+
+    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.
      * 
-     * @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.
+     * 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();
-        /**Tenta carregar diretamente a partir do sistema de ficheiros, se o ficheiro não existir
-         * (por exemplo quando executado a partir do classpath/jar),
-         * faz fallback para carregar a partir do classpath usando o ClassLoader.
-        */
-        IOException lastException = null; //FIXME: melhorar esta parte para reportar erros de forma mais clara
 
-        try {
-            try (InputStream input = new FileInputStream(filePath)) {
-                properties.load(input);
-                return; // carregado com sucesso a partir do caminho fornecido
-            }
+        // 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) {
-            lastException = e;
-            //tenta carregar a partir do classpath sem prefixos comuns
-            String resourcePath = filePath;
-            //Remove prefixos que apontam para src/main/resources quando presentes
-            resourcePath = resourcePath.replace("src/main/resources/", "").replace("src\\main\\resources\\", "");
-            //Remove prefixo classpath: se fornecido
-            if (resourcePath.startsWith("classpath:")) {
-                resourcePath = resourcePath.substring("classpath:".length());
-                if (resourcePath.startsWith("/")) resourcePath = resourcePath.substring(1);
-            }
+            fileSystemException = e;
+            attemptedPaths.add("File system: " + filePath);
+        }
 
-            InputStream resourceStream = Thread.currentThread().getContextClassLoader().getResourceAsStream(resourcePath);
-            if (resourceStream == null) {
-                //como último recurso, tentar com um leading slash
-                resourceStream = SimulationConfig.class.getResourceAsStream('/' + resourcePath);
-            }
+        // Strategy 2: Try to load from classpath with path normalization
+        String resourcePath = filePath;
 
-            if (resourceStream != null) {
-                try (InputStream input = resourceStream) {
-                    properties.load(input);
-                    return;
-                }
+        // 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);
             }
         }
-        if (lastException != null) throw lastException;
+
+        // 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").
      */
@@ -79,6 +172,7 @@ public class SimulationConfig {
 
     /**
      * Gets the port number for a specific intersection.
+     * 
      * @param intersectionId The ID of the intersection (e.g., "Cr1").
      * @return The port number.
      */
@@ -88,6 +182,7 @@ public class SimulationConfig {
 
     /**
      * Gets the host address for the dashboard server.
+     * 
      * @return The dashboard host.
      */
     public String getDashboardHost() {
@@ -96,6 +191,7 @@ public class SimulationConfig {
 
     /**
      * Gets the port number for the dashboard server.
+     * 
      * @return The dashboard port.
      */
     public int getDashboardPort() {
@@ -104,6 +200,7 @@ public class SimulationConfig {
 
     /**
      * Gets the host address for the exit node.
+     * 
      * @return The exit node host.
      */
     public String getExitHost() {
@@ -112,6 +209,7 @@ public class SimulationConfig {
 
     /**
      * Gets the port number for the exit node.
+     * 
      * @return The exit node port.
      */
     public int getExitPort() {
@@ -122,14 +220,26 @@ public class SimulationConfig {
 
     /**
      * 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() {
@@ -139,6 +249,7 @@ public class SimulationConfig {
     /**
      * 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() {
@@ -147,6 +258,7 @@ public class SimulationConfig {
 
     /**
      * Gets the fixed time interval between vehicle arrivals for the FIXED model.
+     * 
      * @return The fixed interval in seconds.
      */
     public double getFixedArrivalInterval() {
@@ -157,8 +269,9 @@ public class SimulationConfig {
 
     /**
      * 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").
+     * @param direction      The direction of the light (e.g., "North").
      * @return The green light time in seconds.
      */
     public double getTrafficLightGreenTime(String intersectionId, String direction) {
@@ -168,8 +281,9 @@ public class SimulationConfig {
 
     /**
      * 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").
+     * @param direction      The direction of the light (e.g., "North").
      * @return The red light time in seconds.
      */
     public double getTrafficLightRedTime(String intersectionId, String direction) {
@@ -181,6 +295,7 @@ public class SimulationConfig {
 
     /**
      * 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() {
@@ -189,6 +304,7 @@ public class SimulationConfig {
 
     /**
      * Gets the average time it takes a LIGHT vehicle to cross an intersection.
+     * 
      * @return The crossing time in seconds.
      */
     public double getLightVehicleCrossingTime() {
@@ -197,6 +313,7 @@ public class SimulationConfig {
 
     /**
      * 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() {
@@ -205,6 +322,7 @@ public class SimulationConfig {
 
     /**
      * Gets the average time it takes a BIKE vehicle to cross an intersection.
+     * 
      * @return The crossing time in seconds.
      */
     public double getBikeVehicleCrossingTime() {
@@ -213,6 +331,7 @@ public class SimulationConfig {
 
     /**
      * 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() {
@@ -221,27 +340,59 @@ public class SimulationConfig {
 
     /**
      * 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"));
     }
 
+    /**
+     * 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"));
+    }
+
+    /**
+     * 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", "10.0"));
+        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 key          The property key.
      * @param defaultValue The value to return if the key is not found.
      * @return The property value or the default.
      */
@@ -251,6 +402,7 @@ public class SimulationConfig {
 
     /**
      * Generic method to get any property as a string.
+     * 
      * @param key The property key.
      * @return The property value, or null if not found.
      */

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

@@ -82,7 +82,7 @@ public class CoordinatorProcess {
 
         System.out.println("Connecting to intersection processes...");
 
-        String[] intersectionIds = {"Cr1", "Cr2", "Cr3", "Cr4", "Cr5"};
+        String[] intersectionIds = { "Cr1", "Cr2", "Cr3", "Cr4", "Cr5" };
 
         for (String intersectionId : intersectionIds) {
             try {
@@ -119,11 +119,30 @@ public class CoordinatorProcess {
         nextGenerationTime = vehicleGenerator.getNextArrivalTime(currentTime);
         final double TIME_STEP = 0.1;
 
-        while (running && currentTime < duration) {
-            if (currentTime >= nextGenerationTime) {
-                generateAndSendVehicle();
-                nextGenerationTime = vehicleGenerator.getNextArrivalTime(currentTime);
+        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;
         }
 
@@ -138,7 +157,7 @@ public class CoordinatorProcess {
         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());
+                currentTime, vehicle.getId(), vehicle.getType(), vehicle.getRoute());
 
         // Send generation count to dashboard
         sendGenerationStatsToDashboard();
@@ -162,11 +181,10 @@ public class CoordinatorProcess {
 
         try {
             Message message = new Message(
-                MessageType.VEHICLE_SPAWN,
-                "COORDINATOR",
-                intersectionId,
-                vehicle
-            );
+                    MessageType.VEHICLE_SPAWN,
+                    "COORDINATOR",
+                    intersectionId,
+                    vehicle);
 
             client.send(message);
             System.out.printf("->Sent to %s%n", intersectionId);
@@ -189,11 +207,10 @@ public class CoordinatorProcess {
             try {
                 if (client.isConnected()) {
                     Message personalizedShutdown = new Message(
-                        MessageType.SHUTDOWN,
-                        "COORDINATOR",
-                        intersectionId,
-                        "Simulation complete"
-                    );
+                            MessageType.SHUTDOWN,
+                            "COORDINATOR",
+                            intersectionId,
+                            "Simulation complete");
                     client.send(personalizedShutdown);
                     System.out.println("Sent shutdown message to " + intersectionId);
                 }
@@ -239,14 +256,13 @@ public class CoordinatorProcess {
             payload.setTotalVehiclesGenerated(vehicleCounter);
 
             Message message = new Message(
-                MessageType.STATS_UPDATE,
-                "COORDINATOR",
-                "Dashboard",
-                payload
-            );
+                    MessageType.STATS_UPDATE,
+                    "COORDINATOR",
+                    "Dashboard",
+                    payload);
 
             dashboardClient.send(message);
-        } catch (Exception e) { //This is fine - can add IOException if need be
+        } 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());
         }
@@ -259,11 +275,10 @@ public class CoordinatorProcess {
         for (Map.Entry<String, SocketClient> entry : intersectionClients.entrySet()) {
             try {
                 Message message = new Message(
-                    MessageType.SIMULATION_START,
-                    "COORDINATOR",
-                    entry.getKey(),
-                    startTimeMillis
-                );
+                        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());
@@ -274,11 +289,10 @@ public class CoordinatorProcess {
         if (dashboardClient != null && dashboardClient.isConnected()) {
             try {
                 Message message = new Message(
-                    MessageType.SIMULATION_START,
-                    "COORDINATOR",
-                    "Dashboard",
-                    startTimeMillis
-                );
+                        MessageType.SIMULATION_START,
+                        "COORDINATOR",
+                        "Dashboard",
+                        startTimeMillis);
                 dashboardClient.send(message);
             } catch (Exception e) { // And here
                 // Don't crash

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

@@ -12,10 +12,10 @@ 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.TitledPane;
 import javafx.scene.control.cell.PropertyValueFactory;
 import javafx.scene.layout.BorderPane;
 import javafx.scene.layout.GridPane;
@@ -23,10 +23,7 @@ import javafx.scene.layout.HBox;
 import javafx.scene.layout.Priority;
 import javafx.scene.layout.Region;
 import javafx.scene.layout.VBox;
-import javafx.scene.paint.Color;
 import javafx.scene.shape.Circle;
-import javafx.scene.text.Font;
-import javafx.scene.text.FontWeight;
 import javafx.stage.Stage;
 import sd.config.SimulationConfig;
 import sd.model.VehicleType;
@@ -62,8 +59,8 @@ public class DashboardUI extends Application {
         try {
             // Initialize server
             String configFile = getParameters().getRaw().isEmpty()
-                ? "src/main/resources/simulation.properties" 
-                : getParameters().getRaw().get(0);
+                    ? "src/main/resources/simulation.properties"
+                    : getParameters().getRaw().get(0);
 
             SimulationConfig config = new SimulationConfig(configFile);
             server = new DashboardServer(config);
@@ -74,7 +71,7 @@ public class DashboardUI extends Application {
 
             // Build UI
             BorderPane root = new BorderPane();
-            root.setStyle("-fx-background-color: #f5f5f5;");
+            root.getStyleClass().add("root");
 
             // Header
             VBox header = createHeader();
@@ -89,7 +86,12 @@ public class DashboardUI extends Application {
             root.setBottom(footer);
 
             // Create scene
-            Scene scene = new Scene(root, 1200, 800);
+            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();
@@ -102,153 +104,204 @@ public class DashboardUI extends Application {
                 shutdown();
             });
 
-        } catch (IOException e) {
+        } catch (Exception e) {
             showErrorAlert("Failed to start Dashboard Server", e.getMessage());
+            e.printStackTrace();
             Platform.exit();
         }
     }
 
     private VBox createHeader() {
         VBox header = new VBox(10);
-        header.setPadding(new Insets(20));
-        header.setStyle("-fx-background-color: linear-gradient(to right, #2c3e50, #3498db);");
+        header.getStyleClass().add("header");
+        header.setAlignment(Pos.CENTER);
 
         Label title = new Label("DISTRIBUTED TRAFFIC SIMULATION DASHBOARD");
-        title.setFont(Font.font("Arial", FontWeight.BOLD, 28));
-        title.setTextFill(Color.WHITE);
+        title.getStyleClass().add("header-title");
 
         Label subtitle = new Label("Real-time Statistics and Monitoring");
-        subtitle.setFont(Font.font("Arial", FontWeight.NORMAL, 16));
-        subtitle.setTextFill(Color.web("#ecf0f1"));
+        subtitle.getStyleClass().add("header-subtitle");
 
-        header.getChildren().addAll(title, subtitle);
-        header.setAlignment(Pos.CENTER);
+        // 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(15);
+        VBox mainContent = new VBox(20);
         mainContent.setPadding(new Insets(20));
 
         // Global Statistics Panel
-        TitledPane globalStatsPane = createGlobalStatisticsPanel();
+        VBox globalStatsCard = createGlobalStatisticsPanel();
+
+        // Tables Container
+        HBox tablesContainer = new HBox(20);
+        tablesContainer.setAlignment(Pos.TOP_CENTER);
 
         // Vehicle Type Statistics Panel
-        TitledPane vehicleTypePane = createVehicleTypePanel();
+        VBox vehicleTypeCard = createVehicleTypePanel();
+        HBox.setHgrow(vehicleTypeCard, Priority.ALWAYS);
 
         // Intersection Statistics Panel
-        TitledPane intersectionPane = createIntersectionPanel();
+        VBox intersectionCard = createIntersectionPanel();
+        HBox.setHgrow(intersectionCard, Priority.ALWAYS);
 
-        mainContent.getChildren().addAll(globalStatsPane, vehicleTypePane, intersectionPane);
+        tablesContainer.getChildren().addAll(vehicleTypeCard, intersectionCard);
+
+        mainContent.getChildren().addAll(globalStatsCard, tablesContainer);
 
         return mainContent;
     }
 
-    private TitledPane createGlobalStatisticsPanel() {
+    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.setPadding(new Insets(15));
-        grid.setHgap(20);
+        grid.getStyleClass().add("card-content");
+        grid.setHgap(40);
         grid.setVgap(15);
-        grid.setStyle("-fx-background-color: white; -fx-border-radius: 5;");
+        grid.setAlignment(Pos.CENTER);
 
         // Initialize labels
-        lblVehiclesGenerated = createStatLabel("0");
-        lblVehiclesCompleted = createStatLabel("0");
-        lblVehiclesInTransit = createStatLabel("0");
-        lblAvgSystemTime = createStatLabel("0.00 ms");
-        lblAvgWaitingTime = createStatLabel("0.00 ms");
+        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, "Total Vehicles Generated:", lblVehiclesGenerated);
-        addStatRow(grid, 1, "Total Vehicles Completed:", lblVehiclesCompleted);
-        addStatRow(grid, 2, "Vehicles In Transit:", lblVehiclesInTransit);
-        addStatRow(grid, 3, "Average System Time:", lblAvgSystemTime);
-        addStatRow(grid, 4, "Average Waiting Time:", lblAvgWaitingTime);
+        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);
 
-        TitledPane pane = new TitledPane("Global Statistics", grid);
-        pane.setCollapsible(false);
-        pane.setFont(Font.font("Arial", FontWeight.BOLD, 16));
-        
-        return pane;
+        card.getChildren().addAll(cardHeader, grid);
+        return card;
     }
 
-    private TitledPane createVehicleTypePanel() {
+    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(200);
+        vehicleTypeTable.setPrefHeight(300);
 
         TableColumn<VehicleTypeRow, String> typeCol = new TableColumn<>("Vehicle Type");
         typeCol.setCellValueFactory(new PropertyValueFactory<>("vehicleType"));
-        typeCol.setPrefWidth(200);
 
         TableColumn<VehicleTypeRow, Integer> countCol = new TableColumn<>("Count");
         countCol.setCellValueFactory(new PropertyValueFactory<>("count"));
-        countCol.setPrefWidth(150);
 
         TableColumn<VehicleTypeRow, String> avgWaitCol = new TableColumn<>("Avg Wait Time");
         avgWaitCol.setCellValueFactory(new PropertyValueFactory<>("avgWaitTime"));
-        avgWaitCol.setPrefWidth(150);
 
         vehicleTypeTable.getColumns().addAll(typeCol, countCol, avgWaitCol);
 
-        TitledPane pane = new TitledPane("Vehicle Type Statistics", vehicleTypeTable);
-        pane.setCollapsible(false);
-        pane.setFont(Font.font("Arial", FontWeight.BOLD, 16));
-        
-        return pane;
+        card.getChildren().addAll(cardHeader, vehicleTypeTable);
+        return card;
     }
 
-    private TitledPane createIntersectionPanel() {
+    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(250);
+        intersectionTable.setPrefHeight(300);
 
         TableColumn<IntersectionRow, String> idCol = new TableColumn<>("Intersection ID");
         idCol.setCellValueFactory(new PropertyValueFactory<>("intersectionId"));
-        idCol.setPrefWidth(200);
 
         TableColumn<IntersectionRow, Integer> arrivalsCol = new TableColumn<>("Total Arrivals");
         arrivalsCol.setCellValueFactory(new PropertyValueFactory<>("arrivals"));
-        arrivalsCol.setPrefWidth(150);
 
         TableColumn<IntersectionRow, Integer> departuresCol = new TableColumn<>("Total Departures");
         departuresCol.setCellValueFactory(new PropertyValueFactory<>("departures"));
-        departuresCol.setPrefWidth(150);
 
         TableColumn<IntersectionRow, Integer> queueCol = new TableColumn<>("Current Queue");
         queueCol.setCellValueFactory(new PropertyValueFactory<>("queueSize"));
-        queueCol.setPrefWidth(150);
 
         intersectionTable.getColumns().addAll(idCol, arrivalsCol, departuresCol, queueCol);
 
-        TitledPane pane = new TitledPane("Intersection Statistics", intersectionTable);
-        pane.setCollapsible(false);
-        pane.setFont(Font.font("Arial", FontWeight.BOLD, 16));
-        
-        return pane;
+        card.getChildren().addAll(cardHeader, intersectionTable);
+        return card;
     }
 
     private HBox createFooter() {
         HBox footer = new HBox(10);
-        footer.setPadding(new Insets(10, 20, 10, 20));
-        footer.setStyle("-fx-background-color: #34495e;");
+        footer.getStyleClass().add("footer");
         footer.setAlignment(Pos.CENTER_LEFT);
 
         Label statusLabel = new Label("Status:");
-        statusLabel.setTextFill(Color.WHITE);
-        statusLabel.setFont(Font.font("Arial", FontWeight.BOLD, 12));
+        statusLabel.getStyleClass().add("footer-text");
+        statusLabel.setStyle("-fx-font-weight: bold;");
 
         Circle statusIndicator = new Circle(6);
-        statusIndicator.setFill(Color.LIME);
+        statusIndicator.setFill(javafx.scene.paint.Color.LIME);
 
         Label statusText = new Label("Connected and Receiving Data");
-        statusText.setTextFill(Color.WHITE);
-        statusText.setFont(Font.font("Arial", 12));
+        statusText.getStyleClass().add("footer-text");
 
         lblLastUpdate = new Label("Last Update: --:--:--");
-        lblLastUpdate.setTextFill(Color.web("#ecf0f1"));
-        lblLastUpdate.setFont(Font.font("Arial", 12));
+        lblLastUpdate.getStyleClass().add("footer-text");
 
         Region spacer = new Region();
         HBox.setHgrow(spacer, Priority.ALWAYS);
@@ -258,27 +311,29 @@ public class DashboardUI extends Application {
         return footer;
     }
 
-    private Label createStatLabel(String initialValue) {
+    private Label createStatValueLabel(String initialValue) {
         Label label = new Label(initialValue);
-        label.setFont(Font.font("Arial", FontWeight.BOLD, 20));
-        label.setTextFill(Color.web("#2980b9"));
+        label.getStyleClass().add("stat-value");
         return label;
     }
 
-    private void addStatRow(GridPane grid, int row, String description, Label valueLabel) {
-        Label descLabel = new Label(description);
-        descLabel.setFont(Font.font("Arial", FontWeight.NORMAL, 14));
-        descLabel.setTextFill(Color.web("#34495e"));
+    private void addStatRow(GridPane grid, int row, int colGroup, String description, Label valueLabel) {
+        VBox container = new VBox(5);
+        container.setAlignment(Pos.CENTER_LEFT);
 
-        grid.add(descLabel, 0, row);
-        grid.add(valueLabel, 1, row);
+        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, 5, TimeUnit.SECONDS);
+        }, 0, 100, TimeUnit.MILLISECONDS);
     }
 
     private void updateUI() {
@@ -286,9 +341,9 @@ public class DashboardUI extends Application {
         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 ms", statistics.getAverageSystemTime()));
-        lblAvgWaitingTime.setText(String.format("%.2f ms", statistics.getAverageWaitingTime()));
+                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
@@ -297,20 +352,18 @@ public class DashboardUI extends Application {
             int count = statistics.getVehicleTypeCount(type);
             double avgWait = statistics.getAverageWaitingTimeByType(type);
             vehicleTypeTable.getItems().add(new VehicleTypeRow(
-                type.toString(), count, String.format("%.2f ms", avgWait)));
+                    type.toString(), count, String.format("%.2f s", avgWait / 1000.0)));
         }
 
         // Update intersection table
         intersectionTable.getItems().clear();
-        Map<String, DashboardStatistics.IntersectionStats> intersectionStats = 
-            statistics.getAllIntersectionStats();
+        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()
-            ));
+                    stats.getIntersectionId(),
+                    stats.getTotalArrivals(),
+                    stats.getTotalDepartures(),
+                    stats.getCurrentQueueSize()));
         }
     }
 
@@ -352,9 +405,17 @@ public class DashboardUI extends Application {
             this.avgWaitTime = avgWaitTime;
         }
 
-        public String getVehicleType() { return vehicleType; }
-        public int getCount() { return count; }
-        public String getAvgWaitTime() { return avgWaitTime; }
+        public String getVehicleType() {
+            return vehicleType;
+        }
+
+        public int getCount() {
+            return count;
+        }
+
+        public String getAvgWaitTime() {
+            return avgWaitTime;
+        }
     }
 
     public static class IntersectionRow {
@@ -370,9 +431,20 @@ public class DashboardUI extends Application {
             this.queueSize = queueSize;
         }
 
-        public String getIntersectionId() { return intersectionId; }
-        public int getArrivals() { return arrivals; }
-        public int getDepartures() { return departures; }
-        public int getQueueSize() { return 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/engine/SimulationEngine.java

@@ -1,628 +0,0 @@
-package sd.engine;
-
-import java.util.HashMap;
-import java.util.Map;
-import java.util.PriorityQueue;
-
-import sd.config.SimulationConfig;
-import sd.model.Event;
-import sd.model.EventType;
-import sd.model.Intersection;
-import sd.model.TrafficLight;
-import sd.model.TrafficLightState;
-import sd.model.Vehicle;
-import sd.model.VehicleType;
-import sd.util.StatisticsCollector;
-import sd.util.VehicleGenerator;
-
-/**
- * Core simulation engine using discrete event simulation (DES).
- * * This class orchestrates the entire simulation. It maintains a
- * {@link PriorityQueue} of {@link Event} objects, representing all
- * scheduled future actions. The engine processes events in strict
- * chronological order (based on their timestamp).
- * * It manages the simulation's state, including:
- * - The current simulation time ({@code currentTime}).
- * - The collection of all {@link Intersection} objects.
- * - The {@link VehicleGenerator} for creating new vehicles.
- * - The {@link StatisticsCollector} for tracking metrics.
- */
-public class SimulationEngine {
-    
-    /**
-     * Holds all simulation parameters loaded from the properties file.
-     */
-    private final SimulationConfig config;
-    
-    /**
-     * The core of the discrete event simulation. Events are pulled from this
-     * queue in order of their timestamp.
-     */
-    private final PriorityQueue<Event> eventQueue;
-    
-    /**
-     * A map storing all intersections in the simulation, keyed by their ID (e.g., "Cr1").
-     */
-    private final Map<String, Intersection> intersections;
-    
-    /**
-     * Responsible for creating new vehicles according to the configured arrival model.
-     */
-    private final VehicleGenerator vehicleGenerator;
-    
-    /**
-     * Collects and calculates statistics throughout the simulation.
-     */
-    private final StatisticsCollector statisticsCollector;
-    
-    /**
-     * The current time in the simulation (in virtual seconds).
-     * This time advances based on the timestamp of the event being processed.
-     */
-    private double currentTime;
-    
-    /**
-     * A simple counter to generate unique IDs for vehicles.
-     */
-    private int vehicleCounter;
-    
-    /**
-     * Constructs a new SimulationEngine.
-     *
-     * @param config The {@link SimulationConfig} object containing all
-     * simulation parameters.
-     */
-    public SimulationEngine(SimulationConfig config) {
-        this.config = config;
-        this.eventQueue = new PriorityQueue<>();
-        this.intersections = new HashMap<>();
-        this.vehicleGenerator = new VehicleGenerator(config);
-        this.statisticsCollector = new StatisticsCollector(config);
-        this.currentTime = 0.0;
-        this.vehicleCounter = 0;
-    }
-    
-    /**
-     * Initializes the simulation. This involves:
-     * 1. Creating all {@link Intersection} and {@link TrafficLight} objects.
-     * 2. Configuring the routing logic between intersections.
-     * 3. Scheduling the initial events (first traffic light changes,
-     * first vehicle generation, and periodic statistics updates).
-     */
-    public void initialize() {
-        System.out.println("Initializing simulation...");
-        
-        setupIntersections();
-        setupRouting();
-        
-        // Schedule initial events to "bootstrap" the simulation
-        scheduleTrafficLightEvents();
-        scheduleNextVehicleGeneration(0.0);
-        scheduleStatisticsUpdates();
-        
-        System.out.println("Simulation initialized with " + intersections.size() + " intersections");
-    }
-    
-    /**
-     * Creates all intersections defined in the configuration
-     * and adds their corresponding traffic lights.
-     */
-    private void setupIntersections() {
-        String[] intersectionIds = {"Cr1", "Cr2", "Cr3", "Cr4", "Cr5"};
-        // Note: "North" is commented out, so it won't be created.
-        String[] directions = {/*"North",*/ "South", "East", "West"};
-        
-        for (String id : intersectionIds) {
-            Intersection intersection = new Intersection(id);
-            
-            // Add traffic lights for each configured direction
-            for (String direction : directions) {
-                double greenTime = config.getTrafficLightGreenTime(id, direction);
-                double redTime = config.getTrafficLightRedTime(id, direction);
-                
-                TrafficLight light = new TrafficLight(
-                    id + "-" + direction,
-                    direction,
-                    greenTime,
-                    redTime
-                );
-                
-                intersection.addTrafficLight(light);
-            }
-            
-            intersections.put(id, intersection);
-        }
-    }
-    
-    /**
-     * Configures how vehicles should be routed between intersections.
-     * This hardcoded logic defines the "map" of the city.
-     * * For example, `intersections.get("Cr1").configureRoute("Cr2", "East");` means
-     * "at intersection Cr1, any vehicle whose *next* destination is Cr2
-     * should be sent to the 'East' traffic light queue."
-     */
-    private void setupRouting() {
-        // Cr1 routing
-        intersections.get("Cr1").configureRoute("Cr2", "East");
-        intersections.get("Cr1").configureRoute("Cr4", "South");
-        
-        // Cr2 routing
-        intersections.get("Cr2").configureRoute("Cr1", "West");
-        intersections.get("Cr2").configureRoute("Cr3", "East");
-        intersections.get("Cr2").configureRoute("Cr5", "South");
-        
-        // Cr3 routing
-        intersections.get("Cr3").configureRoute("Cr2", "West");
-        intersections.get("Cr3").configureRoute("S", "South"); // "S" is the exit
-        
-        // Cr4 routing
-        //intersections.get("Cr4").configureRoute("Cr1", "North");
-        intersections.get("Cr4").configureRoute("Cr5", "East");
-        
-        // Cr5 routing
-        //intersections.get("Cr5").configureRoute("Cr2", "North");
-        //intersections.get("Cr5").configureRoute("Cr4", "West");
-        intersections.get("Cr5").configureRoute("S", "East"); // "S" is the exit
-    }
-    
-    /**
-     * Schedules the initial {@link EventType#TRAFFIC_LIGHT_CHANGE} event
-     * for every traffic light in the simulation.
-     * A small random delay is added to "stagger" the lights, preventing
-     * all of them from changing at the exact same time at t=0.
-     */
-    private void scheduleTrafficLightEvents() {
-        for (Intersection intersection : intersections.values()) {
-            for (TrafficLight light : intersection.getTrafficLights()) {
-                // Start with lights in RED state, schedule first GREEN change
-                // Stagger the start times slightly to avoid all lights changing at once
-                double staggerDelay = Math.random() * 1.5;
-                scheduleTrafficLightChange(light, intersection.getId(), staggerDelay);
-            }
-        }
-    }
-    
-    /**
-     * Creates and schedules a new {@link EventType#TRAFFIC_LIGHT_CHANGE} event.
-     * The event is scheduled to occur at {@code currentTime + delay}.
-     *
-     * @param light The {@link TrafficLight} that will change state.
-     * @param intersectionId The ID of the intersection where the light is located.
-     * @param delay The time (in seconds) from {@code currentTime} when the change should occur.
-     */
-    private void scheduleTrafficLightChange(TrafficLight light, String intersectionId, double delay) {
-        double changeTime = currentTime + delay;
-        Event event = new Event(changeTime, EventType.TRAFFIC_LIGHT_CHANGE, light, intersectionId);
-        eventQueue.offer(event);
-    }
-    
-    /**
-     * Schedules the next {@link EventType#VEHICLE_GENERATION} event.
-     * The time of the next arrival is determined by the {@link VehicleGenerator}.
-     *
-     * @param baseTime The time from which to calculate the next arrival (usually {@code currentTime}).
-     */
-    private void scheduleNextVehicleGeneration(double baseTime) {
-        // Get the absolute time for the next arrival.
-        double nextArrivalTime = vehicleGenerator.getNextArrivalTime(baseTime);
-        
-        // Only schedule the event if it's within the simulation's total duration.
-        if (nextArrivalTime < config.getSimulationDuration()) {
-            Event event = new Event(nextArrivalTime, EventType.VEHICLE_GENERATION, null, null);
-            eventQueue.offer(event);
-        }
-    }
-    
-    /**
-     * Schedules all periodic {@link EventType#STATISTICS_UPDATE} events
-     * for the entire duration of the simulation.
-     */
-    private void scheduleStatisticsUpdates() {
-        double interval = config.getStatisticsUpdateInterval();
-        double duration = config.getSimulationDuration();
-        
-        for (double time = interval; time < duration; time += interval) {
-            Event event = new Event(time, EventType.STATISTICS_UPDATE, null, null);
-            eventQueue.offer(event);
-        }
-    }
-    
-    /**
-     * Runs the main simulation loop.
-     * The loop continues as long as there are events in the queue and
-     * the {@code currentTime} is less than the total simulation duration.
-     * * In each iteration, it:
-     * 1. Polls the next event from the {@link #eventQueue}.
-     * 2. Advances {@link #currentTime} to the event's timestamp.
-     * 3. Calls {@link #processEvent(Event)} to handle the event.
-     * * After the loop, it prints the final statistics.
-     */
-    public void run() {
-        System.out.println("Starting simulation...");
-        double duration = config.getSimulationDuration();
-        
-        while (!eventQueue.isEmpty() && currentTime < duration) {
-            // Get the next event in chronological order
-            Event event = eventQueue.poll();
-            
-            // Advance simulation time to this event's time
-            currentTime = event.getTimestamp();
-            
-            // Process the event
-            processEvent(event);
-        }
-        
-        System.out.println("\nSimulation completed at t=" + String.format("%.2f", currentTime) + "s");
-        printFinalStatistics();
-    }
-    
-    /**
-     * Main event processing logic.
-     * Delegates the event to the appropriate handler method based on its {@link EventType}.
-     *
-     * @param event The {@link Event} to be processed.
-     */
-    private void processEvent(Event event) {
-        switch (event.getType()) {
-            case VEHICLE_GENERATION -> handleVehicleGeneration();
-                
-            case VEHICLE_ARRIVAL -> handleVehicleArrival(event);
-                
-            case TRAFFIC_LIGHT_CHANGE -> handleTrafficLightChange(event);
-                
-            case CROSSING_START -> handleCrossingStart(event);
-                
-            case CROSSING_END -> handleCrossingEnd(event);
-                
-            case STATISTICS_UPDATE -> handleStatisticsUpdate();
-                
-            default -> System.err.println("Unknown event type: " + event.getType());
-        }
-    }
-    
-    /**
-     * Handles {@link EventType#VEHICLE_GENERATION}.
-     * 1. Creates a new {@link Vehicle} using the {@link #vehicleGenerator}.
-     * 2. Records the generation event with the {@link #statisticsCollector}.
-     * 3. Schedules a {@link EventType#VEHICLE_ARRIVAL} event for the vehicle
-     * at its first destination intersection.
-     * 4. Schedules the *next* {@link EventType#VEHICLE_GENERATION} event.
-     * (Note: This line is commented out in the original, which might be a bug,
-     * as it implies only one vehicle is ever generated. It should likely be active.)
-     */
-    private void handleVehicleGeneration() {
-        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());
-        
-        // Register with statistics collector
-        statisticsCollector.recordVehicleGeneration(vehicle, currentTime);
-        
-        // Schedule arrival at first intersection
-        String firstIntersection = vehicle.getCurrentDestination();
-        if (firstIntersection != null && !firstIntersection.equals("S")) {
-            // Assume minimal travel time to first intersection (e.g., 1-3 seconds)
-            double arrivalTime = currentTime + 1.0 + Math.random() * 2.0;
-            Event arrivalEvent = new Event(arrivalTime, EventType.VEHICLE_ARRIVAL, vehicle, firstIntersection);
-            eventQueue.offer(arrivalEvent);
-        }
-        
-        // Schedule next vehicle generation
-        // This was commented out in the original file.
-        // For a continuous simulation, it should be enabled:
-        scheduleNextVehicleGeneration(currentTime);
-    }
-    
-    /**
-     * Handles {@link EventType#VEHICLE_ARRIVAL} at an intersection.
-     * 1. Records the arrival for statistics.
-     * 2. Advances the vehicle's internal route planner to its *next* destination.
-     * 3. If the next destination is the exit ("S") or null,
-     * the vehicle exits the system via {@link #handleVehicleExit(Vehicle)}.
-     * 4. Otherwise, the vehicle is placed in the correct queue at the
-     * current intersection using {@link Intersection#receiveVehicle(Vehicle)}.
-     * 5. Attempts to process the vehicle immediately if its light is green.
-     *
-     * @param event The arrival event, containing the {@link Vehicle} and intersection ID.
-     */
-    private void handleVehicleArrival(Event event) {
-        Vehicle vehicle = (Vehicle) event.getData();
-        String intersectionId = event.getLocation();
-        
-        Intersection intersection = intersections.get(intersectionId);
-        if (intersection == null) {
-            System.err.println("Unknown intersection: " + intersectionId);
-            return;
-        }
-        
-        System.out.printf("[t=%.2f] Vehicle %s arrived at %s%n",
-            currentTime, vehicle.getId(), intersectionId);
-        
-        // Record arrival time (used to calculate waiting time later)
-        statisticsCollector.recordVehicleArrival(vehicle, intersectionId, currentTime);
-        
-        // Advance the vehicle's route to the *next* stop
-        // (it has now arrived at its *current* destination)
-        boolean hasNext = vehicle.advanceRoute();
-        
-        if (!hasNext) {
-            // This was the last stop
-            handleVehicleExit(vehicle);
-            return;
-        }
-        
-        String nextDestination = vehicle.getCurrentDestination();
-        if (nextDestination == null || "S".equals(nextDestination)) {
-            // Next stop is the exit
-            handleVehicleExit(vehicle);
-            return;
-        }
-        
-        // Add vehicle to the appropriate traffic light queue based on its next destination
-        intersection.receiveVehicle(vehicle);
-        
-        // Try to process the vehicle immediately if its light is already green
-        tryProcessVehicle(vehicle, intersection);
-    }
-    
-    /**
-     * Checks if a newly arrived vehicle (or a vehicle in a queue
-     * that just turned green) can start crossing.
-     *
-     * @param vehicle The vehicle to process.
-     * @param intersection The intersection where the vehicle is.
-     */
-    private void tryProcessVehicle(Vehicle vehicle, Intersection intersection) { //FIXME
-        // Find the direction (and light) this vehicle is queued at
-        // This logic is a bit flawed: it just finds the *first* non-empty queue
-        // A better approach would be to get the light from the vehicle's route
-        String direction = intersection.getTrafficLights().stream()
-            .filter(tl -> tl.getQueueSize() > 0)
-            .map(TrafficLight::getDirection)
-            .findFirst()
-            .orElse(null);
-        
-        if (direction != null) {
-            TrafficLight light = intersection.getTrafficLight(direction);
-            // If the light is green and it's the correct one...
-            if (light != null && light.getState() == TrafficLightState.GREEN) {
-                // ...remove the vehicle from the queue (if it's at the front)
-                Vehicle v = light.removeVehicle();
-                if (v != null) {
-                    // ...and schedule its crossing.
-                    scheduleCrossing(v, intersection);
-                }
-            }
-        }
-    }
-    
-    /**
-     * Schedules the crossing for a vehicle that has just been dequeued
-     * from a green light.
-     * 1. Calculates and records the vehicle's waiting time.
-     * 2. Schedules an immediate {@link EventType#CROSSING_START} event.
-     *
-     * @param vehicle The {@link Vehicle} that is crossing.
-     * @param intersection The {@link Intersection} it is crossing.
-     */
-    private void scheduleCrossing(Vehicle vehicle, Intersection intersection) {
-        // Calculate time spent waiting at the red light
-        double waitTime = currentTime - statisticsCollector.getArrivalTime(vehicle);
-        vehicle.addWaitingTime(waitTime);
-        
-        // Schedule crossing start event *now*
-        Event crossingStart = new Event(currentTime, EventType.CROSSING_START, vehicle, intersection.getId());
-        processEvent(crossingStart); // Process immediately
-    }
-    
-    /**
-     * Handles {@link EventType#CROSSING_START}.
-     * 1. Determines the crossing time based on vehicle type.
-     * 2. Schedules a {@link EventType#CROSSING_END} event to occur
-     * at {@code currentTime + crossingTime}.
-     *
-     * @param event The crossing start event.
-     */
-    private void handleCrossingStart(Event event) {
-        Vehicle vehicle = (Vehicle) event.getData();
-        String intersectionId = event.getLocation();
-        
-        double crossingTime = getCrossingTime(vehicle.getType());
-        
-        System.out.printf("[t=%.2f] Vehicle %s started crossing at %s (duration=%.2fs)%n",
-            currentTime, vehicle.getId(), intersectionId, crossingTime);
-        
-        // Schedule the *end* of the crossing
-        double endTime = currentTime + crossingTime;
-        Event crossingEnd = new Event(endTime, EventType.CROSSING_END, vehicle, intersectionId);
-        eventQueue.offer(crossingEnd);
-    }
-    
-    /**
-     * Handles {@link EventType#CROSSING_END}.
-     * 1. Updates intersection and vehicle statistics.
-     * 2. Checks the vehicle's *next* destination.
-     * 3. If the next destination is the exit ("S"), call {@link #handleVehicleExit(Vehicle)}.
-     * 4. Otherwise, schedule a {@link EventType#VEHICLE_ARRIVAL} event at the
-     * *next* intersection, after some travel time.
-     *
-     * @param event The crossing end event.
-     */
-    private void handleCrossingEnd(Event event) {
-        Vehicle vehicle = (Vehicle) event.getData();
-        String intersectionId = event.getLocation();
-        
-        // Update stats
-        Intersection intersection = intersections.get(intersectionId);
-        if (intersection != null) {
-            intersection.incrementVehiclesSent();
-        }
-        
-        double crossingTime = getCrossingTime(vehicle.getType());
-        vehicle.addCrossingTime(crossingTime);
-        
-        System.out.printf("[t=%.2f] Vehicle %s finished crossing at %s%n",
-            currentTime, vehicle.getId(), intersectionId);
-        
-        // Decide what to do next
-        String nextDest = vehicle.getCurrentDestination();
-        if (nextDest != null && !nextDest.equals("S")) {
-            // Route to the *next* intersection
-            // Assume 5-10 seconds travel time between intersections
-            double travelTime = 5.0 + Math.random() * 5.0; 
-            double arrivalTime = currentTime + travelTime;
-            Event arrivalEvent = new Event(arrivalTime, EventType.VEHICLE_ARRIVAL, vehicle, nextDest);
-            eventQueue.offer(arrivalEvent);
-        } else {
-            // Reached the exit
-            handleVehicleExit(vehicle);
-        }
-    }
-    
-    /**
-     * Handles a vehicle exiting the simulation.
-     * Records final statistics for the vehicle.
-     *
-     * @param vehicle The {@link Vehicle} that has completed its route.
-     */
-    private void handleVehicleExit(Vehicle vehicle) {
-        System.out.printf("[t=%.2f] Vehicle %s exited the system (wait=%.2fs, travel=%.2fs)%n",
-            currentTime, vehicle.getId(), 
-            vehicle.getTotalWaitingTime(), 
-            vehicle.getTotalTravelTime(currentTime));
-        
-        // Record the exit for final statistics calculation
-        statisticsCollector.recordVehicleExit(vehicle, currentTime);
-    }
-    
-    /**
-     * Handles {@link EventType#TRAFFIC_LIGHT_CHANGE}.
-     * 1. Toggles the light's state (RED to GREEN or GREEN to RED).
-     * 2. If the light just turned GREEN, call {@link #processGreenLight(TrafficLight, Intersection)}
-     * to process any waiting vehicles.
-     * 3. Schedules the *next* state change for this light based on its
-     * green/red time duration.
-     *
-     * @param event The light change event.
-     */
-    private void handleTrafficLightChange(Event event) {
-        TrafficLight light = (TrafficLight) event.getData();
-        String intersectionId = event.getLocation();
-        
-        // Toggle state
-        TrafficLightState newState = (light.getState() == TrafficLightState.RED) 
-            ? TrafficLightState.GREEN 
-            : TrafficLightState.RED;
-        
-        light.changeState(newState);
-        
-        System.out.printf("[t=%.2f] Traffic light %s changed to %s%n",
-            currentTime, light.getId(), newState);
-        
-        // If changed to GREEN, process waiting vehicles
-        if (newState == TrafficLightState.GREEN) {
-            Intersection intersection = intersections.get(intersectionId);
-            if (intersection != null) {
-                processGreenLight(light, intersection);
-            }
-        }
-        
-        // Schedule the *next* state change for this same light
-        double nextChangeDelay = (newState == TrafficLightState.GREEN) 
-            ? light.getGreenTime() 
-            : light.getRedTime();
-        
-        scheduleTrafficLightChange(light, intersectionId, nextChangeDelay);
-    }
-    
-    /**
-     * Processes vehicles when a light turns green.
-     * It loops as long as the light is green and there are vehicles in the queue,
-     * dequeuing one vehicle at a time and scheduling its crossing.
-     * * *Note*: This is a simplified model. A real simulation would
-     * account for the *time* it takes each vehicle to cross, processing
-     * one vehicle every {@code crossingTime} seconds. This implementation
-     * processes the entire queue "instantaneously" at the moment
-     * the light turns green.
-     *
-     * @param light The {@link TrafficLight} that just turned green.
-     * @param intersection The {@link Intersection} where the light is.
-     */
-    private void processGreenLight(TrafficLight light, Intersection intersection) {
-        // While the light is green and vehicles are waiting...
-        while (light.getState() == TrafficLightState.GREEN && light.getQueueSize() > 0) {
-            Vehicle vehicle = light.removeVehicle();
-            if (vehicle != null) {
-                // Dequeue one vehicle and schedule its crossing
-                scheduleCrossing(vehicle, intersection);
-            }
-        }
-    }
-    
-    /**
-     * Handles {@link EventType#STATISTICS_UPDATE}.
-     * Calls the {@link StatisticsCollector} to print the current
-     * state of the simulation (queue sizes, averages, etc.).
-     */
-    private void handleStatisticsUpdate() {
-        System.out.printf("\n=== Statistics at t=%.2f ===%n", currentTime);
-        statisticsCollector.printCurrentStatistics(intersections, currentTime);
-        System.out.println();
-    }
-    
-    /**
-     * Utility method to get the configured crossing time for a given {@link VehicleType}.
-     *
-     * @param type The type of vehicle.
-     * @return The crossing time in seconds.
-     */
-    private double getCrossingTime(VehicleType type) {
-        return switch (type) {
-            case BIKE -> config.getBikeVehicleCrossingTime();
-            case LIGHT -> config.getLightVehicleCrossingTime();
-            case HEAVY -> config.getHeavyVehicleCrossingTime();
-            default -> 2.0;
-        }; // Default fallback
-    }
-    
-    /**
-     * Prints the final summary of statistics at the end of the simulation.
-     */
-    private void printFinalStatistics() {
-        System.out.println("\n" + "=".repeat(60));
-        System.out.println("FINAL SIMULATION STATISTICS");
-        System.out.println("=".repeat(60));
-        
-        statisticsCollector.printFinalStatistics(intersections, currentTime);
-        
-        System.out.println("=".repeat(60));
-    }
-    
-    // --- Public Getters ---
-
-    /**
-     * Gets the current simulation time.
-     * @return The time in virtual seconds.
-     */
-    public double getCurrentTime() {
-        return currentTime;
-    }
-    
-    /**
-     * Gets a map of all intersections in the simulation.
-     * Returns a copy to prevent external modification.
-     * @return A {@link Map} of intersection IDs to {@link Intersection} objects.
-     */
-    public Map<String, Intersection> getIntersections() {
-        return new HashMap<>(intersections);
-    }
-    
-    /**
-     * Gets the statistics collector instance.
-     * @return The {@link StatisticsCollector}.
-     */
-    public StatisticsCollector getStatisticsCollector() {
-        return statisticsCollector;
-    }
-}

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

@@ -44,14 +44,12 @@ public class TrafficLightThread implements Runnable {
                     light.changeState(TrafficLightState.GREEN);
                     System.out.println("[" + light.getId() + "] State: GREEN");
 
-                    processGreenLightQueue();
+                    // Process queue for the duration of the green light
+                    long greenDurationMs = (long) (light.getGreenTime() * 1000);
+                    processGreenLightQueue(greenDurationMs);
 
-                    if (!running || Thread.currentThread().isInterrupted()) break;
-                    
-                    // Wait for green duration
-                    Thread.sleep((long) (light.getGreenTime() * 1000));
-                    
-                    if (!running || Thread.currentThread().isInterrupted()) break;
+                    if (!running || Thread.currentThread().isInterrupted())
+                        break;
 
                     // --- RED Phase ---
                     light.changeState(TrafficLightState.RED);
@@ -74,21 +72,34 @@ public class TrafficLightThread implements Runnable {
         }
     }
 
-    private void processGreenLightQueue() throws InterruptedException {
+    private void processGreenLightQueue(long greenDurationMs) throws InterruptedException {
+        long startTime = System.currentTimeMillis();
+
         while (running && !Thread.currentThread().isInterrupted()
-               && light.getState() == TrafficLightState.GREEN 
-               && light.getQueueSize() > 0) {
+                && light.getState() == TrafficLightState.GREEN) {
 
-            Vehicle vehicle = light.removeVehicle();
+            // Check if green time has expired
+            long elapsed = System.currentTimeMillis() - startTime;
+            if (elapsed >= greenDurationMs) {
+                break;
+            }
 
-            if (vehicle != null) {
-                double crossingTime = getCrossingTimeForVehicle(vehicle);
+            if (light.getQueueSize() > 0) {
+                Vehicle vehicle = light.removeVehicle();
 
-                Thread.sleep((long) (crossingTime * 1000));
+                if (vehicle != null) {
+                    double crossingTime = getCrossingTimeForVehicle(vehicle);
+                    long crossingTimeMs = (long) (crossingTime * 1000);
 
-                vehicle.addCrossingTime(crossingTime);
-                process.getIntersection().incrementVehiclesSent();
-                process.sendVehicleToNextDestination(vehicle);
+                    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);
             }
         }
     }

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

@@ -1,131 +0,0 @@
-package sd.model;
-
-import java.io.Serializable;
-
-/**
- * Represents a single event in the discrete event simulation.
- * * An Event is the fundamental unit of action in the simulation. It contains:
- * - A {@code timestamp} (when the event should occur).
- * - A {@link EventType} (what kind of event it is).
- * - Associated {@code data} (e.g., the {@link Vehicle} or {@link TrafficLight} involved).
- * - An optional {@code location} (e.g., the ID of the {@link Intersection}).
- * * Events are {@link Comparable}, allowing them to be sorted in a
- * {@link java.util.PriorityQueue}. The primary sorting key is the
- * {@code timestamp}. If timestamps are equal, {@code EventType} is used
- * as a tie-breaker to ensure a consistent, deterministic order.
- * * Implements {@link Serializable} so events could (in theory) be sent
- * across a network in a distributed simulation.
- */
-public class Event implements Comparable<Event>, Serializable {
-    private static final long serialVersionUID = 1L;
-    
-    /**
-     * The simulation time (in seconds) when this event is scheduled to occur.
-     */
-    private final double timestamp;
-    
-    /**
-     * The type of event (e.g., VEHICLE_ARRIVAL, TRAFFIC_LIGHT_CHANGE).
-     */
-    private final EventType type;
-    
-    /**
-     * The data payload associated with this event.
-     * This could be a {@link Vehicle}, {@link TrafficLight}, or null.
-     */
-    private final Object data;
-    
-    /**
-     * The ID of the location where the event occurs (e.g., "Cr1").
-     * Can be null if the event is not location-specific (like VEHICLE_GENERATION).
-     */
-    private final String location;
-    
-    /**
-     * Constructs a new Event.
-     *
-     * @param timestamp The simulation time when the event occurs.
-     * @param type The {@link EventType} of the event.
-     * @param data The associated data (e.g., a Vehicle object).
-     * @param location The ID of the location (e.g., an Intersection ID).
-     */
-    public Event(double timestamp, EventType type, Object data, String location) {
-        this.timestamp = timestamp;
-        this.type = type;
-        this.data = data;
-        this.location = location;
-    }
-    
-    /**
-     * Convenience constructor for an Event without a specific location.
-     *
-     * @param timestamp The simulation time when the event occurs.
-     * @param type The {@link EventType} of the event.
-     * @param data The associated data (e.g., a Vehicle object).
-     */
-    public Event(double timestamp, EventType type, Object data) {
-        this(timestamp, type, data, null);
-    }
-    
-    /**
-     * Compares this event to another event for ordering.
-     * * Events are ordered primarily by {@link #timestamp} (ascending).
-     * If timestamps are identical, they are ordered by {@link #type} (alphabetical)
-     * to provide a stable, deterministic tie-breaking mechanism.
-     *
-     * @param other The other Event to compare against.
-     * @return A negative integer if this event comes before {@code other},
-     * zero if they are "equal" in sorting (though this is rare),
-     * or a positive integer if this event comes after {@code other}.
-     */
-    @Override
-    public int compareTo(Event other) {
-        // Primary sort: timestamp (earlier events come first)
-        int cmp = Double.compare(this.timestamp, other.timestamp);
-        if (cmp == 0) {
-            // Tie-breaker: event type (ensures deterministic order)
-            return this.type.compareTo(other.type);
-        }
-        return cmp;
-    }
-    
-    // --- Getters ---
-    
-    /**
-     * @return The simulation time when the event occurs.
-     */
-    public double getTimestamp() {
-        return timestamp;
-    }
-    
-    /**
-     * @return The {@link EventType} of the event.
-     */
-    public EventType getType() {
-        return type;
-    }
-    
-    /**
-     * @return The data payload (e.g., {@link Vehicle}, {@link TrafficLight}).
-     * The caller must cast this to the expected type.
-     */
-    public Object getData() {
-        return data;
-    }
-    
-    /**
-     * @return The location ID (e.g., "Cr1"), or null if not applicable.
-     */
-    public String getLocation() {
-        return location;
-    }
-    
-    /**
-     * @return A string representation of the event for logging.
-     */
-    @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

@@ -1,45 +0,0 @@
-package sd.model;
-
-/**
- * Enumeration representing all possible event types in the discrete event simulation.
- * These types are used by the {@link sd.engine.SimulationEngine} to determine
- * how to process a given {@link Event}.
- */
-public enum EventType {
-    
-    /**
-     * Fired when a {@link Vehicle} arrives at an {@link Intersection}.
-     * Data: {@link Vehicle}, Location: Intersection ID
-     */
-    VEHICLE_ARRIVAL,
-    
-    /**
-     * Fired when a {@link TrafficLight} is scheduled to change its state.
-     * Data: {@link TrafficLight}, Location: Intersection ID
-     */
-    TRAFFIC_LIGHT_CHANGE,
-    
-    /**
-     * Fired when a {@link Vehicle} begins to cross an {@link Intersection}.
-     * Data: {@link Vehicle}, Location: Intersection ID
-     */
-    CROSSING_START,
-    
-    /**
-     * Fired when a {@link Vehicle} finishes crossing an {@link Intersection}.
-     * Data: {@link Vehicle}, Location: Intersection ID
-     */
-    CROSSING_END,
-    
-    /**
-     * Fired when a new {@link Vehicle} should be created and added to the system.
-     * Data: null, Location: null
-     */
-    VEHICLE_GENERATION,
-    
-    /**
-     * Fired periodically to trigger the printing or sending of simulation statistics.
-     * Data: null, Location: null
-     */
-    STATISTICS_UPDATE
-}

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

@@ -140,6 +140,16 @@ public class Intersection {
         }
     }
 
+    /**
+     * 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.
      *

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

@@ -12,7 +12,7 @@ import java.util.List;
  * - 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 {@link Event}
+ * * 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).
@@ -67,10 +67,11 @@ public class Vehicle implements Serializable {
     /**
      * Constructs a new Vehicle.
      *
-     * @param id The unique ID for the vehicle.
-     * @param type The {@link VehicleType}.
+     * @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"]).
+     * @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;
@@ -90,8 +91,8 @@ public class Vehicle implements Serializable {
      * 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.
+     *         in the route, {@code false} if the vehicle has passed its
+     *         final destination.
      */
     public boolean advanceRoute() {
         currentRouteIndex++;
@@ -103,7 +104,7 @@ public class Vehicle implements Serializable {
      * the vehicle is heading towards.
      *
      * @return The ID of the current destination (e.g., "Cr1"), or
-     * {@code null} if the route is complete.
+     *         {@code null} if the route is complete.
      */
     public String getCurrentDestination() {
         return (currentRouteIndex < route.size()) ? route.get(currentRouteIndex) : null;
@@ -113,7 +114,7 @@ public class Vehicle implements Serializable {
      * 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.
+     *         of the route list, {@code false} otherwise.
      */
     public boolean hasReachedEnd() {
         return currentRouteIndex >= route.size();
@@ -151,7 +152,8 @@ public class Vehicle implements Serializable {
     }
 
     /**
-     * @return The current index pointing to the vehicle's destination in its route list.
+     * @return The current index pointing to the vehicle's destination in its route
+     *         list.
      */
     public int getCurrentRouteIndex() {
         return currentRouteIndex;
@@ -199,7 +201,7 @@ public class Vehicle implements Serializable {
      *
      * @param currentTime The current simulation time.
      * @return The total elapsed time (in seconds) since the vehicle
-     * was generated ({@code currentTime - entryTime}).
+     *         was generated ({@code currentTime - entryTime}).
      */
     public double getTotalTravelTime(double currentTime) {
         return currentTime - entryTime;
@@ -211,8 +213,7 @@ public class Vehicle implements Serializable {
     @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/protocol/SocketConnection.java

@@ -4,7 +4,6 @@ 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;
@@ -127,7 +126,7 @@ public class SocketConnection implements Closeable {
      * @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 void sendMessage(MessageProtocol message) throws IOException {
+    public synchronized void sendMessage(MessageProtocol message) throws IOException {
    if (socket == null || !socket.isConnected()) {
             throw new IOException("Socket is not connected");
         }

main/src/main/java/sd/serialization/SerializationExample.java

@@ -1,134 +0,0 @@
-package sd.serialization;
-
-import sd.model.Message;
-import sd.model.MessageType;
-import sd.model.Vehicle;
-import sd.model.VehicleType;
-
-import java.util.Arrays;
-import java.util.List;
-
-/**
- * Demonstration of JSON serialization usage in the traffic simulation system.
- * 
- * This class shows practical examples of how to use JSON (Gson) serialization
- * for network communication between simulation processes.
- */
-public class SerializationExample {
-    
-    public static void main(String[] args) {
-        System.out.println("=== JSON Serialization Example ===\n");
-        
-        // Create a sample vehicle
-        List<String> route = Arrays.asList("Cr1", "Cr2", "Cr5", "S");
-        Vehicle vehicle = new Vehicle("V001", VehicleType.LIGHT, 10.5, route);
-        vehicle.addWaitingTime(2.3);
-        vehicle.addCrossingTime(1.2);
-        
-        // Create a message containing the vehicle
-        Message message = new Message(
-            MessageType.VEHICLE_TRANSFER,
-            "Cr1",
-            "Cr2",
-            vehicle
-        );
-        
-        // ===== JSON Serialization =====
-        demonstrateJsonSerialization(message);
-        
-        // ===== Factory Usage =====
-        demonstrateFactoryUsage(message);
-        
-        // ===== Performance Test =====
-        performanceTest(message);
-    }
-    
-    private static void demonstrateJsonSerialization(Message message) {
-        System.out.println("--- JSON Serialization ---");
-        
-        try {
-            // Create JSON serializer with pretty printing for readability
-            MessageSerializer serializer = new JsonMessageSerializer(true);
-            
-            // Serialize to bytes
-            byte[] data = serializer.serialize(message);
-            
-            // Display the JSON
-            String json = new String(data);
-            System.out.println("Serialized JSON (" + data.length + " bytes):");
-            System.out.println(json);
-            
-            // Deserialize back
-            Message deserialized = serializer.deserialize(data, Message.class);
-            System.out.println("\nDeserialized: " + deserialized);
-            System.out.println("✓ JSON serialization successful\n");
-            
-        } catch (SerializationException e) {
-            System.err.println("❌ JSON serialization failed: " + e.getMessage());
-        }
-    }
-    
-    private static void demonstrateFactoryUsage(Message message) {
-        System.out.println("--- Using SerializerFactory ---");
-        
-        try {
-            // Get default serializer (JSON)
-            MessageSerializer serializer = SerializerFactory.createDefault();
-            System.out.println("Default serializer: " + serializer.getName());
-            
-            // Use it
-            byte[] data = serializer.serialize(message);
-            Message deserialized = serializer.deserialize(data, Message.class);
-            
-            System.out.println("Message type: " + deserialized.getType());
-            System.out.println("From: " + deserialized.getSenderId() + 
-                             " → To: " + deserialized.getDestinationId());
-            System.out.println("✓ Factory usage successful\n");
-            
-        } catch (SerializationException e) {
-            System.err.println("❌ Factory usage failed: " + e.getMessage());
-        }
-    }
-    
-    private static void performanceTest(Message message) {
-        System.out.println("--- Performance Test ---");
-        
-        int iterations = 1000;
-        
-        try {
-            MessageSerializer compactSerializer = new JsonMessageSerializer(false);
-            MessageSerializer prettySerializer = new JsonMessageSerializer(true);
-            
-            // Warm up
-            for (int i = 0; i < 100; i++) {
-                compactSerializer.serialize(message);
-            }
-            
-            // Test compact JSON
-            long compactStart = System.nanoTime();
-            byte[] compactData = null;
-            for (int i = 0; i < iterations; i++) {
-                compactData = compactSerializer.serialize(message);
-            }
-            long compactTime = System.nanoTime() - compactStart;
-            
-            // Test pretty JSON
-            byte[] prettyData = prettySerializer.serialize(message);
-            
-            // Results
-            System.out.println("Iterations: " + iterations);
-            System.out.println("\nJSON Compact:");
-            System.out.println("  Size: " + compactData.length + " bytes");
-            System.out.println("  Time: " + (compactTime / 1_000_000.0) + " ms total");
-            System.out.println("  Avg:  " + (compactTime / iterations / 1_000.0) + " μs/operation");
-            
-            System.out.println("\nJSON Pretty-Print:");
-            System.out.println("  Size: " + prettyData.length + " bytes");
-            System.out.println("  Size increase: " + 
-                String.format("%.1f%%", ((double)prettyData.length / compactData.length - 1) * 100));
-            
-        } catch (SerializationException e) {
-            System.err.println("❌ Performance test failed: " + e.getMessage());
-        }
-    }
-}

main/src/main/java/sd/util/StatisticsCollector.java

@@ -1,379 +0,0 @@
-package sd.util;
-
-import java.util.ArrayList;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
-
-import sd.config.SimulationConfig;
-import sd.model.Intersection;
-import sd.model.Vehicle;
-import sd.model.VehicleType;
-
-/**
- * Collects, manages, and reports statistics throughout the simulation.
- * * This class acts as the central bookkeeper for simulation metrics. It tracks:
- * - Overall system statistics (total vehicles, completion time, wait time).
- * - Per-vehicle-type statistics (counts, average wait time by type).
- * - Per-intersection statistics (arrivals, departures).
- * * It also maintains "in-flight" data, such as the arrival time of a
- * vehicle at its *current* intersection, which is necessary to
- * calculate waiting time when the vehicle later departs.
- */
-public class StatisticsCollector {
-    
-    // --- Vehicle tracking (for in-flight vehicles) ---
-    
-    /**
-     * Tracks the simulation time when a vehicle arrives at its *current* intersection.
-     * This is used later to calculate waiting time (Depart_Time - Arrive_Time).
-     * Key: Vehicle ID (String)
-     * Value: Arrival Time (Double)
-     */
-    private final Map<String, Double> vehicleArrivalTimes;
-    
-    /**
-     * Tracks the sequence of intersections a vehicle has visited.
-     * Key: Vehicle ID (String)
-     * Value: List of Intersection IDs (String)
-     */
-    private final Map<String, List<String>> vehicleIntersectionHistory;
-    
-    // --- Overall system statistics ---
-    
-    /** Total number of vehicles created by the {@link VehicleGenerator}. */
-    private int totalVehiclesGenerated;
-    
-    /** Total number of vehicles that have reached their final destination ("S"). */
-    private int totalVehiclesCompleted;
-    
-    /** The sum of all *completed* vehicles' total travel times. Used for averaging. */
-    private double totalSystemTime;
-    
-    /** The sum of all *completed* vehicles' total waiting times. Used for averaging. */
-    private double totalWaitingTime;
-    
-    // --- Per-vehicle-type statistics ---
-    
-    /**
-     * Tracks the total number of vehicles generated, broken down by type.
-     * Key: {@link VehicleType}
-     * Value: Count (Integer)
-     */
-    private final Map<VehicleType, Integer> vehicleTypeCount;
-    
-    /**
-     * Tracks the total waiting time, broken down by vehicle type.
-     * Key: {@link VehicleType}
-     * Value: Total Wait Time (Double)
-     */
-    private final Map<VehicleType, Double> vehicleTypeWaitTime;
-    
-    // --- Per-intersection statistics ---
-    
-    /**
-     * A map to hold statistics objects for each intersection.
-     * Key: Intersection ID (String)
-     * Value: {@link IntersectionStats} object
-     */
-    private final Map<String, IntersectionStats> intersectionStats;
-    
-    /**
-     * Constructs a new StatisticsCollector.
-     * Initializes all maps and counters.
-     *
-     * @param config The {@link SimulationConfig} (not currently used, but
-     * could be for configuration-dependent stats).
-     */
-    public StatisticsCollector(SimulationConfig config) {
-        this.vehicleArrivalTimes = new HashMap<>();
-        this.vehicleIntersectionHistory = new HashMap<>();
-        this.totalVehiclesGenerated = 0;
-        this.totalVehiclesCompleted = 0;
-        this.totalSystemTime = 0.0;
-        this.totalWaitingTime = 0.0;
-        this.vehicleTypeCount = new HashMap<>();
-        this.vehicleTypeWaitTime = new HashMap<>();
-        this.intersectionStats = new HashMap<>();
-        
-        // Initialize vehicle type counters to 0
-        for (VehicleType type : VehicleType.values()) {
-            vehicleTypeCount.put(type, 0);
-            vehicleTypeWaitTime.put(type, 0.0);
-        }
-    }
-    
-    /**
-     * Records that a new vehicle has been generated.
-     * This is called by the {@link sd.engine.SimulationEngine}
-     * during a {@code VEHICLE_GENERATION} event.
-     *
-     * @param vehicle The {@link Vehicle} that was just created.
-     * @param currentTime The simulation time of the event.
-     */
-    public void recordVehicleGeneration(Vehicle vehicle, double currentTime) {
-        totalVehiclesGenerated++;
-        
-        // Track by vehicle type
-        VehicleType type = vehicle.getType();
-        vehicleTypeCount.put(type, vehicleTypeCount.get(type) + 1);
-        
-        // Initialize history tracking for this vehicle
-        vehicleIntersectionHistory.put(vehicle.getId(), new ArrayList<>());
-    }
-    
-    /**
-     * Records that a vehicle has arrived at an intersection queue.
-     * This is called by the {@link sd.engine.SimulationEngine}
-     * during a {@code VEHICLE_ARRIVAL} event.
-     *
-     * @param vehicle The {@link Vehicle} that arrived.
-     * @param intersectionId The ID of the intersection it arrived at.
-     * @param currentTime The simulation time of the arrival.
-     */
-    public void recordVehicleArrival(Vehicle vehicle, String intersectionId, double currentTime) {
-        // Store arrival time - this is the "start waiting" time
-        vehicleArrivalTimes.put(vehicle.getId(), currentTime);
-        
-        // Track intersection history
-        List<String> history = vehicleIntersectionHistory.get(vehicle.getId());
-        if (history != null) {
-            history.add(intersectionId);
-        }
-        
-        // Update per-intersection statistics
-        getOrCreateIntersectionStats(intersectionId).recordArrival();
-    }
-    
-    /**
-     * Records that a vehicle has completed its route and exited the system.
-     * This is where final metrics for the vehicle are aggregated.
-     * This is called by the {@link sd.engine.SimulationEngine}
-     * when a vehicle reaches destination "S".
-     *
-     * @param vehicle The {@link Vehicle} that is exiting.
-     * @param currentTime The simulation time of the exit.
-     */
-    public void recordVehicleExit(Vehicle vehicle, double currentTime) {
-        totalVehiclesCompleted++;
-        
-        // Calculate and aggregate total system time
-        double systemTime = vehicle.getTotalTravelTime(currentTime);
-        totalSystemTime += systemTime;
-        
-        // Aggregate waiting time
-        double waitTime = vehicle.getTotalWaitingTime();
-        totalWaitingTime += waitTime;
-        
-        // Aggregate waiting time by vehicle type
-        VehicleType type = vehicle.getType();
-        vehicleTypeWaitTime.put(type, vehicleTypeWaitTime.get(type) + waitTime);
-        
-        // Clean up tracking maps to save memory
-        vehicleArrivalTimes.remove(vehicle.getId());
-        vehicleIntersectionHistory.remove(vehicle.getId());
-    }
-    
-    /**
-     * Gets the time a vehicle arrived at its *current* intersection.
-     * This is used by the {@link sd.engine.SimulationEngine} to calculate
-     * wait time just before the vehicle crosses.
-     *
-     * @param vehicle The {@link Vehicle} to check.
-     * @return The arrival time, or 0.0 if not found.
-     */
-    public double getArrivalTime(Vehicle vehicle) {
-        return vehicleArrivalTimes.getOrDefault(vehicle.getId(), 0.0);
-    }
-    
-    /**
-     * Prints a "snapshot" of the current simulation statistics.
-     * This is called periodically by the {@link sd.engine.SimulationEngine}
-     * during a {@code STATISTICS_UPDATE} event.
-     *
-     * @param intersections A map of all intersections (to get queue data).
-     * @param currentTime The current simulation time.
-     */
-    public void printCurrentStatistics(Map<String, Intersection> intersections, double currentTime) {
-        System.out.printf("--- Statistics at t=%.2f ---%n", currentTime);
-        System.out.printf("Vehicles: Generated=%d, Completed=%d, In-System=%d%n",
-            totalVehiclesGenerated,
-            totalVehiclesCompleted,
-            totalVehiclesGenerated - totalVehiclesCompleted);
-        
-        if (totalVehiclesCompleted > 0) {
-            System.out.printf("Average System Time (so far): %.2fs%n", totalSystemTime / totalVehiclesCompleted);
-            System.out.printf("Average Waiting Time (so far): %.2fs%n", totalWaitingTime / totalVehiclesCompleted);
-        }
-        
-        // Print per-intersection queue sizes
-        System.out.println("\nIntersection Queues:");
-        for (Map.Entry<String, Intersection> entry : intersections.entrySet()) {
-            String id = entry.getKey();
-            Intersection intersection = entry.getValue();
-            System.out.printf("  %s: Queue=%d, Received=%d, Sent=%d%n",
-                id,
-                intersection.getTotalQueueSize(),
-                intersection.getTotalVehiclesReceived(),
-                intersection.getTotalVehiclesSent());
-        }
-    }
-    
-    /**
-     * Prints the final simulation summary statistics at the end of the run.
-     *
-     * @param intersections A map of all intersections.
-     * @param currentTime The final simulation time.
-     */
-    public void printFinalStatistics(Map<String, Intersection> intersections, double currentTime) {
-        System.out.println("\n=== SIMULATION SUMMARY ===");
-        System.out.printf("Duration: %.2f seconds%n", currentTime);
-        System.out.printf("Total Vehicles Generated: %d%n", totalVehiclesGenerated);
-        System.out.printf("Total Vehicles Completed: %d%n", totalVehiclesCompleted);
-        System.out.printf("Vehicles Still in System: %d%n", totalVehiclesGenerated - totalVehiclesCompleted);
-        
-        // Overall averages
-        if (totalVehiclesCompleted > 0) {
-            System.out.printf("%nAVERAGE METRICS (for completed vehicles):%n");
-            System.out.printf("  System Time: %.2f seconds%n", totalSystemTime / totalVehiclesCompleted);
-            System.out.printf("  Waiting Time: %.2f seconds%n", totalWaitingTime / totalVehiclesCompleted);
-            System.out.printf("  Throughput: %.2f vehicles/second%n", totalVehiclesCompleted / currentTime);
-        }
-        
-        // Vehicle type breakdown
-        System.out.println("\nVEHICLE TYPE DISTRIBUTION:");
-        for (VehicleType type : VehicleType.values()) {
-            int count = vehicleTypeCount.get(type);
-            if (count > 0) {
-                double percentage = (count * 100.0) / totalVehiclesGenerated;
-                // Calculate avg wait *only* for this type
-                // This assumes all generated vehicles of this type *completed*
-                // A more accurate way would be to track completed vehicle types
-                double avgWait = vehicleTypeWaitTime.get(type) / count; 
-                System.out.printf("  %s: %d (%.1f%%), Avg Wait: %.2fs%n",
-                    type, count, percentage, avgWait);
-            }
-        }
-        
-        // Per-intersection statistics
-        System.out.println("\nINTERSECTION STATISTICS:");
-        for (Map.Entry<String, Intersection> entry : intersections.entrySet()) {
-            String id = entry.getKey();
-            Intersection intersection = entry.getValue();
-            
-            System.out.printf("  %s:%n", id);
-            System.out.printf("    Vehicles Received: %d%n", intersection.getTotalVehiclesReceived());
-            System.out.printf("    Vehicles Sent: %d%n", intersection.getTotalVehiclesSent());
-            System.out.printf("    Final Queue Size: %d%n", intersection.getTotalQueueSize());
-            
-            // Traffic light details
-            intersection.getTrafficLights().forEach(light -> {
-                System.out.printf("      Light %s: State=%s, Queue=%d, Processed=%d%n",
-                    light.getDirection(),
-                    light.getState(),
-                    light.getQueueSize(),
-                    light.getTotalVehiclesProcessed());
-            });
-        }
-        
-        // System health indicators
-        System.out.println("\nSYSTEM HEALTH:");
-        int totalQueuedVehicles = intersections.values().stream()
-            .mapToInt(Intersection::getTotalQueueSize)
-            .sum();
-        System.out.printf("  Total Queued Vehicles (at end): %d%n", totalQueuedVehicles);
-        
-        if (totalVehiclesGenerated > 0) {
-            double completionRate = (totalVehiclesCompleted * 100.0) / totalVehiclesGenerated;
-            System.out.printf("  Completion Rate: %.1f%%%n", completionRate);
-        }
-    }
-    
-    /**
-     * Gets or creates the statistics object for a given intersection.
-     * Uses {@code computeIfAbsent} for efficient, thread-safe-like instantiation.
-     *
-     * @param intersectionId The ID of the intersection.
-     * @return The {@link IntersectionStats} object for that ID.
-     */
-    private IntersectionStats getOrCreateIntersectionStats(String intersectionId) {
-        // If 'intersectionId' is not in the map, create a new IntersectionStats()
-        // and put it in the map, then return it.
-        // Otherwise, just return the one that's already there.
-        return intersectionStats.computeIfAbsent(intersectionId, k -> new IntersectionStats());
-    }
-    
-    /**
-     * Inner class to track per-intersection statistics.
-     * This is a simple data holder.
-     */
-    private static class IntersectionStats {
-        private int totalArrivals;
-        private int totalDepartures;
-        
-        public IntersectionStats() {
-            this.totalArrivals = 0;
-            this.totalDepartures = 0;
-        }
-        
-        public void recordArrival() {
-            totalArrivals++;
-        }
-        
-        public void recordDeparture() {
-            totalDepartures++;
-        }
-        
-        public int getTotalArrivals() {
-            return totalArrivals;
-        }
-        
-        public int getTotalDepartures() {
-            return totalDepartures;
-        }
-    }
-    
-    // --- Public Getters for Final Statistics ---
-    
-    /**
-     * @return Total vehicles generated during the simulation.
-     */
-    public int getTotalVehiclesGenerated() {
-        return totalVehiclesGenerated;
-    }
-    
-    /**
-     * @return Total vehicles that completed their route.
-     */
-    public int getTotalVehiclesCompleted() {
-        return totalVehiclesCompleted;
-    }
-    
-    /**
-     * @return The sum of all travel times for *completed* vehicles.
-     */
-    public double getTotalSystemTime() {
-        return totalSystemTime;
-    }
-    
-    /**
-     * @return The sum of all waiting times for *completed* vehicles.
-     */
-    public double getTotalWaitingTime() {
-        return totalWaitingTime;
-    }
-    
-    /**
-     * @return The average travel time for *completed* vehicles.
-     */
-    public double getAverageSystemTime() {
-        return totalVehiclesCompleted > 0 ? totalSystemTime / totalVehiclesCompleted : 0.0;
-    }
-    
-    /**
-     * @return The average waiting time for *completed* vehicles.
-     */
-    public double getAverageWaitingTime() {
-        return totalVehiclesCompleted > 0 ? totalWaitingTime / totalVehiclesCompleted : 0.0;
-    }
-}

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=60.0
+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/SimulationTest.java

@@ -6,15 +6,11 @@ import static org.junit.jupiter.api.Assertions.assertTrue;
 import org.junit.jupiter.api.Test;
 
 import sd.config.SimulationConfig;
-import sd.engine.SimulationEngine;
-import sd.model.Event;
-import sd.model.EventType;
 import sd.model.Intersection;
 import sd.model.TrafficLight;
 import sd.model.TrafficLightState;
 import sd.model.Vehicle;
 import sd.model.VehicleType;
-import sd.util.StatisticsCollector;
 import sd.util.VehicleGenerator;
 
 /**
@@ -29,7 +25,7 @@ class SimulationTest {
         assertEquals(60.0, config.getSimulationDuration());
         assertEquals("POISSON", config.getArrivalModel());
         assertEquals(0.5, config.getArrivalRate());
-        assertEquals(10.0, config.getStatisticsUpdateInterval());
+        assertEquals(1.0, config.getStatisticsUpdateInterval());
     }
 
     @Test
@@ -46,16 +42,6 @@ class SimulationTest {
         assertTrue(!vehicle.getRoute().isEmpty());
     }
 
-    @Test
-    void testEventOrdering() {
-        Event e1 = new Event(5.0, EventType.VEHICLE_ARRIVAL, null, "Cr1");
-        Event e2 = new Event(3.0, EventType.VEHICLE_ARRIVAL, null, "Cr2");
-        Event e3 = new Event(7.0, EventType.TRAFFIC_LIGHT_CHANGE, null, "Cr1");
-        
-        assertTrue(e2.compareTo(e1) < 0); // e2 should come before e1
-        assertTrue(e1.compareTo(e3) < 0); // e1 should come before e3
-    }
-    
     @Test
     void testIntersectionVehicleQueue() {
         Intersection intersection = new Intersection("TestCr");
@@ -64,7 +50,7 @@ class SimulationTest {
         intersection.addTrafficLight(light);
 
         Vehicle v1 = new Vehicle("V1", VehicleType.LIGHT, 0.0,
-            java.util.Arrays.asList("TestCr", "S"));
+                java.util.Arrays.asList("TestCr", "S"));
 
         intersection.configureRoute("S", "North");
 
@@ -90,36 +76,7 @@ class SimulationTest {
         assertEquals(TrafficLightState.RED, light.getState());
     }
 
-    @Test
-    void testSimulationEngineInitialization() throws IOException {
-        SimulationConfig config = new SimulationConfig("src/main/resources/simulation.properties");
-        SimulationEngine engine = new SimulationEngine(config);
+    // Removed testSimulationEngineInitialization as SimulationEngine has been
+    // removed.
 
-        engine.initialize();
-        
-        assertNotNull(engine.getIntersections());
-        assertEquals(5, engine.getIntersections().size());
-        
-        // Check that intersections have traffic lights
-        for (Intersection intersection : engine.getIntersections().values()) {
-            assertEquals(3, intersection.getTrafficLights().size()); // North, South, East, West
-        }
-    }
-    
-    @Test
-    void testStatisticsCollector() throws IOException {
-        SimulationConfig config = new SimulationConfig("src/main/resources/simulation.properties");
-        StatisticsCollector collector = new StatisticsCollector(config);
-        
-        Vehicle v1 = new Vehicle("V1", VehicleType.LIGHT, 0.0, 
-            java.util.Arrays.asList("Cr1", "Cr2", "S"));
-        
-        collector.recordVehicleGeneration(v1, 0.0);
-        assertEquals(1, collector.getTotalVehiclesGenerated());
-        
-        collector.recordVehicleArrival(v1, "Cr1", 1.0);
-        
-        collector.recordVehicleExit(v1, 10.0);
-        assertEquals(1, collector.getTotalVehiclesCompleted());
-    }
 }

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/TrafficLightCoordinationTest.java

@@ -85,7 +85,7 @@ public class TrafficLightCoordinationTest {
             if (greenCount > 1) {
                 violationCount.incrementAndGet();
                 String violation = String.format("[VIOLATION] %d lights GREEN simultaneously: %s",
-                    greenCount, currentState.toString());
+                        greenCount, currentState.toString());
                 violations.add(violation);
                 System.err.println(violation);
             }
@@ -104,9 +104,9 @@ public class TrafficLightCoordinationTest {
 
         // Assert that we never had more than one green light
         assertEquals(0, violationCount.get(),
-            "Traffic light coordination violated! Multiple lights were GREEN simultaneously.");
+                "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());
+                "At most ONE light should be GREEN at any time. Found: " + maxGreenSimultaneously.get());
 
         System.out.println("\nTraffic light coordination working correctly!");
     }
@@ -133,8 +133,8 @@ public class TrafficLightCoordinationTest {
         List<TrafficLight> lights = intersectionProcess.getIntersection().getTrafficLights();
         boolean[] hasBeenGreen = new boolean[lights.size()];
 
-        // Monitor for 15 seconds (enough time for all lights to cycle)
-        long endTime = System.currentTimeMillis() + 15000;
+        // 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++) {
@@ -152,7 +152,8 @@ public class TrafficLightCoordinationTest {
         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++;
+            if (hasBeenGreen[i])
+                greenCount++;
         }
 
         assertTrue(greenCount > 0, "At least one light should have been GREEN during the test");
@@ -193,7 +194,7 @@ public class TrafficLightCoordinationTest {
                 if (currentState != previousStates[i]) {
                     transitionCount++;
                     System.out.println(lights.get(i).getDirection() + " transitioned: " +
-                        previousStates[i] + " → " + currentState);
+                            previousStates[i] + " → " + currentState);
                     previousStates[i] = currentState;
                 }
             }