public void enterParkedState(int parkingTime, int intendedDuration) throws VehicleException {
		if (isParked || isQueued){
			throw new VehicleException ("Vehicle is already in a parked or queued state");
		}
		if (parkingTime <= 0){
			throw new VehicleException ("Parking Time <= 0");
		}
		if (intendedDuration < Constants.MINIMUM_STAY){
			throw new VehicleException ("IntendedDuration is less than the minimum");
		}
		isParked = true;
		this.parkingTime = parkingTime;
		this.departureTime = parkingTime + intendedDuration;
	}