@Override
    public void update(Observable o, Object arg) {
        if(o instanceof Timer && !(arg == null) && arg instanceof Integer && (Integer)arg <= 36000 && (Integer)arg >= 0){
           int timestamp = (Integer) arg;
           if (timestamp >= nextCar) {
               if (timestamp != 1){
                cs.addToEntryQueue(new Car(rand.nextInt(maxParkduration-minParkduration+1) + minParkduration-1));
               }
               nextCar = createRandInt(timestamp) + timestamp;
           }
       }
    }