After stopping the car I shut off the engine while the gear/selector was still in D (Drive). The car began rolling forward since the driveway has a slope. My car hit the car parked before my car. The front bumper has been damaged. Later. I've checked several times this situation: If engine shuts off while selector is in D, the vehicle rolls instead of holding on a slope. This is a serious safety issue! Many driveways have slopes.