# 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..

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. To pass, the applicant must answer at least 20 questions correctly. Test questions come from the Georgia Commercial Driver’s Manual. Questions come from 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. What kind of force must emergency brakes use?

Explanation
Because air pressure can eventually leak away, the emergency brakes in an air brake system must be held on by mechanical force.

### 8. An air brake-equipped vehicle traveling at a speed of 55 mph under ideal driving conditions will need approximately ____ to come to a complete stop.

Explanation
A vehicle's total stopping distance is made up of perception distance, reaction distance, brake lag distance, and braking distance. With all of these factors included, an air brake-equipped vehicle traveling at a speed of 55 mph under ideal driving conditions will need approximately 450 feet to come to a complete stop.

### 9. 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.

### 10. Before a vehicle with dual air brakes is driven, pressure of at least ____ should be built up in both braking systems.

Explanation
Before driving a vehicle with a dual air brake system, allow time for the air compressor to build up pressure of at least 100 psi in both the primary and secondary systems.

### 11. The brake pedal is part of which braking system?

Explanation
The service brake system applies and releases the brakes when a driver presses the brake pedal while driving normally.

### 12. Before driving a vehicle with a dual air brake system, you must wait for the air compressor to build a minimum of ____ in both the primary and secondary systems.

Explanation
Before driving a vehicle with a dual air brake system, you should wait for the air compressor to build up at least 100 psi in both the primary and secondary systems.