Final answer:
When parking downhill, turn the wheels towards the curb, apply the parking brake, and leave the vehicle in gear (or 'park') for safety.
Step-by-step explanation:
When parking a vehicle facing downhill, the appropriate steps to ensure safety are: 1) Turn the wheels towards the curb to ensure that if the vehicle were to move, it would roll into the curb and stop, not into the street. 2) Apply the parking brake to give an additional layer of security against the vehicle rolling away. 3) It is also advisable to leave the vehicle in gear (or in 'park' if driving an automatic), never in neutral, to use the engine as an additional method to prevent the vehicle from rolling.