If you park facing downhill on the right side of a road with a curb, you should turn your front wheels

Explanation

If you park downhill on the right side of a road with or without a curb, turn your front wheels to the right. If you park uphill with a curb, turn your front wheels away from the curb. If you park uphill without a curb, turn your front wheels toward the edge of the road. In this way, if your car starts to roll downhill, either the curb will block it or it will at least roll away from traffic.