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 three or four answer choices. To pass, the applicant must answer at least 20 questions correctly. Test questions come from the Mississippi Professional Driver’s 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
7. Braking mechanisms are located inside:
Explanation
Drum brakes are attached to the wheels and located on the axles of a vehicle. The braking mechanisms that cause the vehicle to stop can be found inside of a drum brake.
8. Pressing and releasing the brake pedal unnecessarily can:
Explanation
On a vehicle with air brakes, pressing and releasing the brake pedal unnecessarily may let air out of the braking system faster than the compressor can replace it. This may cause the system's air pressure to become too low and the brakes to stop working.
9. What kind of force do emergency brakes use?
Explanation
Air brakes are really three different braking systems: the service brake, the parking brake, and the emergency brake. Emergency and parking brakes are applied with mechanical force.
10. The service brake system:
Explanation
Air brakes consists of three separate braking systems: the service brake system, the parking brake system, and the emergency brake system. The service brake system applies and releases the brakes when you use the brake pedal while driving normally.
11. To make a stop in a vehicle using air brakes, the driver should:
Explanation
To make a normal stop in an air-braked vehicle, push the brake pedal down and control the pressure so that the vehicle comes to a smooth, safe stop.
12. The ____ between an air compressor and reservoir tank prevents air from escaping if the air compressor has a leak.
Explanation
