Which statement describes the parking brake test?

• A. Vehicle stays stationary on a 20% grade
• B. Vehicle moves on a flat surface
• C. Brakes hold only when the engine is idling
• D. Engine off with the brakes applied no test

Answer: (A)

Parking brake testing checks whether the parking brake can hold the vehicle when there is a tendency to roll, such as on an incline. On a 20% grade, gravity pulls the vehicle downhill, so if the parking brake is functioning properly, the vehicle should remain stationary when the parking brake is applied. This directly demonstrates the brake’s holding power under load, which is exactly what the test is meant to verify. Testing on a flat surface wouldn’t push the brake with a gravitational pull, and statements about holding only with the engine idling or about there being no test don’t describe how the parking brake should perform when the vehicle is on a slope. So the description that the vehicle stays stationary on a 20% grade best captures what the parking brake test assesses.