You have parked facing down a steep hill. Which of the following should you do?

If the brakes fail while your vehicle is facing downhill, the vehicle may start to roll forward. You can set the transmission to oppose this movement. If it's a manual transmission, set it in Reverse. If it's an automatic transmission, set it in Park. (Modern cars with automatic transmissions won't let you remove the ignition key unless the transmission is in Park.) [How to Park on a Hill, Chapter 7 Parallel Parking, Part 2 – Rules of the Road, New York State Driver's Manual]