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.. Read More

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 West Virginia Commercial Driver’s 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. To use the controlled braking method, you should:

Explanation
The method of controlled braking involves applying the brakes as hard as you can without locking the wheels. If you need to make large steering adjustments while using controlled braking, you should remove your foot from the brake pedal, steer, then reapply the brakes.

2. 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.

3. A low air pressure warning signal should activate:

Explanation
In an air brake system, a low air pressure warning signal must come on if air pressure in the tanks falls below 60 psi. This warning signal may come in the form of a light, a buzzer, or a wig wag.

4. To use the stab braking method in an emergency situation, you should:

Explanation
The stab braking method for emergency stops involves fully applying the brakes until they lock up. The brakes are then released until the wheels start rolling, then the process is repeated.

5. Air tanks usually hold enough compressed air:

Explanation
In an air braking system, the air storage tanks can usually hold enough compressed air for the brakes to be used several times.

6. During a static leakage test, the maximum leakage rate for a double combination vehicle is:

Explanation
When performing a static leakage test on a double combination vehicle with air brakes, the leakage rate should be no more than 3 psi in one minute. If air leaks from the air brake system at a quicker rate, the vehicle should not be driven because something likely needs to be repaired.
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