/** Initialisation of the simulation. */
 public static void init() {
   Junction.registerJunctionType(BlockedLaneJunction.class);
   Junction.registerJunctionType(TwoLaneJunction.class);
   Junction.registerJunctionType(TurnJunc.class);
   settings = new HashMap<>();
   settings.put(MIN_DENSITY, 0);
   settings.put(MAX_DENSITY, 0);
   settings.put(AGGRESSION, 0);
   settings.put(CAR_RATIO, 0);
   settings.put(TRUCK_RATIO, 0);
   settings.put(MAXIMUM_SPEED, 0);
   settings.put(JUNCTION_TYPE, null);
   settings.put(TIME_STEP, 0);
   paused = false;
   started = false;
   simulationThread = new SimulationThread();
   new SettingsWindow();
   totalTimeSteps = 0;
 }