Arizona Air Brakes CDL Practice Test

When driving down a long steep hill, what should you do regarding braking?

1. A. Use stab braking.

2. B. Begin braking when you are 10 M.P.H. above your safe speed.

3. C. Release the brake when you are 5 M.P.H. below your safe speed.

4. D. Use the trailer brakes.

The correct answer is: C. Release the brake when you are 5 M.P.H. below your safe speed.

When navigating a long steep hill, it's crucial to manage your speed effectively to maintain control of the vehicle and ensure safety. The correct approach involves beginning to brake when you've exceeded your safe speed and then releasing the brake once you drop to a speed that is within safe limits. Specifically, releasing the brake when you are 5 M.P.H. below your safe speed allows for a more stable and controlled descent. This technique helps prevent overheating of the brakes due to continuous pressure, which is particularly important when descending a steep grade. It also allows for the brakes to cool down slightly, thus maintaining their effectiveness. At the same time, this practice minimizes the risk of losing traction or control, as constant braking can lead to a dangerous scenario. Properly managing your braking in this manner reflects an understanding of how to handle a vehicle's weight and momentum on inclines and declines, which is invaluable for safe driving, particularly in larger vehicles subject to additional considerations with air brakes.