Explantion: In most vehicles, the parking brake operates on the rear wheels only. The function of the parking brake (handbrake) is to stop the vehicle from moving when it is parked or when it is stopped on a hill. Drivers normally use the parking brake when the vehicle is already stationary and should generally not use it to stop the vehicle. It is even more important to use the parking brake when parked on a hill or when stationary in a vehicle with automatic transmission to prevent creep.