Instructions

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 25

Passing Score 20

1. To use the controlled braking method, you should:

Apply the brakes as hard as possible without locking the wheels.

Apply the brakes with about half-force.

Apply the brakes until the wheels lock.

Pump the brakes.

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:

Lock the wheels and skid to a stop.

Stop in a way that keeps your vehicle in a straight line.

Stop in a way that turns your vehicle.

Expect your vehicle to slow down more quickly than usual.

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:

When tank pressure falls below 120 psi.

When tank pressure falls below 60 psi.

When tank pressure falls below 10 psi.

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:

Apply the brakes completely until the wheels lock up, release the brakes until the wheels start rolling, then repeat the process.

Apply the brakes about halfway, but keep the wheels rolling.

Fully apply the brakes, let the wheels lock up, and hold the brake pedal down, keeping the wheels locked until the vehicle stops.

Apply the emergency brake.

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:

For one stop before needing to be refilled.

For several stops before needing to be refilled.

For a day’s worth of braking.

For an unlimited number of stops.

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:

3 psi in one minute.

6 psi in one minute.

8 psi in one minute.

4 psi in one minute.

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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