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 South Dakota 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
1. Most heavy-duty vehicles use ____ air brake systems.
Explanation
The majority of heavy-duty vehicles are equipped with dual air brake systems.
2. 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.
3. Braking mechanisms are located ____ a brake drum.
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.
4. Truck tractors with air brakes that were built on or after March 1, 1997 are equipped with:
Explanation
Truck tractors with air brakes that were manufactured on or after March 1, 1997 are required to be equipped with Anti-Lock Braking Systems (ABS). ABS is required in any other type of vehicle with air brakes that was manufactured on or after March 1, 1998.
5. Failing to drain air tanks could result in:
Explanation
In an air brake system, the air tanks must be periodically drained to remove accumulations of water and compressor oil. If water is not removed, it could freeze in cold weather and cause brake failure.
6. If the spring brakes are activated, you should never:
Explanation
