Air Brakes
This endorsement is required for driving a vehicle with air brakes. To receive this endorsement, applicants must pass a written test. The test consists of 25 multiple choice questions. Each question has four answer choices. To pass, the applicant must answer at least 20 questions correctly. Test questions come from the Colorado Commercial Driver License Manual. Questions come from the chapter covering: Air Brakes. The Air Brakes endorsement may be used with the Class A, B or C CDL.
Number of Question
Passing Score
13. What happens if the air pressure in a system's air tanks falls below 60 psi?
Explanation
In an air brake system, a low pressure warning signal should activate if the pressure in the air tanks falls to a level below 60 psi. This signal may be in the form of a warning light or a wig wag.
14. When you need to stop in an emergency, you should:
Explanation
If you need to make an emergency stop, you can use either the controlled braking method or the stab braking method. It's important to brake in a way that keeps your vehicle traveling in a straight line while still allowing you to turn, if necessary.
15. The air compressor governor controls:
Explanation
In an air brake system, the air compressor governor controls when the air compressor pumps air into the air storage tanks.
16. How many air storage tanks are used in an air brake system?
Explanation
Air storage tanks are used to hold compressed air. The number and size of air tanks in an air brake system varies among vehicles.
17. What does ABS do?
Explanation
The purpose of an Anti-Lock Braking System (ABS) is to prevent wheels from locking up during hard applications of the brakes, especially on slippery surfaces.
18. Brakes may get out of adjustment:
Explanation
