Parking brake holds on what grade?

• A. 10 degree grade
• B. 15 degree grade
• C. 20 degree grade
• D. 25 degree grade

Answer: (C)

When you park a vehicle on a slope, the parking brake must counteract the downhill component of gravity. The grade expressed in degrees tells you how steep that slope is, and the brake is rated to hold the vehicle up to a certain steepness. For this system, the parking brake is designed to hold on grades up to 20 degrees. That means on slopes at or below 20 degrees, the brake’s friction is enough to prevent motion; on steeper slopes, like 25 degrees, the brake could fail to hold and you’d need additional protection such as wheel chocks. The other options describe gentler slopes the brake can handle, but the maximum it can reliably hold is 20 degrees.