A vehicle handbrake or emergency brake stops the rear wheels from turning to stop the car. When parking a standard transmission vehicle on a slope, setting the handbrake keeps the car from rolling. Car owners can use the handbrake to hold the car in place on a hill at a red light or stop sign and release it while depressing the clutch and gas for forward motion. When the brakes suddenly fail on a car, the handbrake will stop the car and prevent accidents. Adjust handbrakes to stop cars fully at the fourth notch on the lever.