public void update(Observable o, Object arg) {
      for (Element<Light> e : _lightElements) {
        System.out.print("Light at (" + e.i + "," + e.j + "): ");

        	System.out.println(e.x.getColor());
      }
      for (Element<VehicleAcceptor> e : _roadElements) {
        for (Vehicle d : e.x.getCars()) {
          System.out.print("Road at (" + e.i + "," + e.j + "): ");
          System.out.println("Car at " + d.getPosition());
        }
      }
    }