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 three answer choices. To pass, the applicant must answer at least 20 questions correctly. Test questions come from the Idaho Commercial Driver’s License Manual l. 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. The ____ are activated by an electric switch that is triggered by the brake pedal.

Headlights

Turn signals

Brake lights

In a vehicle with air brakes, the brake lights are activated when the brake pedal is pushed and air pressure moves an electric switch. With the application of air pressure, the switch will then turn on the brake lights.

2. Why do large vehicles use air brakes?

Other brake systems squeak too loudly.

Air brakes are very effective systems.

Other braking systems are hard to come by.

If used and maintained properly, air brakes are a safe and effective way to stop large, heavy vehicles.

3. When traveling down a steep downgrade:

The air brakes should be used.

The vehicle should be placed in a low gear and the driver should use engine braking.

The driver should continually downshift instead of using the brakes.

On long and/or steep downgrades, you should primarily use engine braking to control the speed of your vehicle. Use your brakes only as a supplement to this effect.

4. Air tank drains should:

Not be used by the driver.

Only be used when it is wet outside.

Be used to drain the tanks completely.

Compressed air in an air brake system usually contains a certain amount of water and compressor oil. The water and oil can damage the brakes if left to accumulate in the system. Manually operated air tank drains must be opened daily to remove this build-up.

5. Emergency brakes:

Are not required on vehicles with air brakes.

Are required only on buses.

Are required on all vehicles.

All trucks, truck tractors, and buses must be equipped with emergency brakes and parking brakes.

6. You should ____ if the low pressure warning signal activates while you are driving.

Stop where you are and park

Exit the roadway as soon as safely possible

Continue driving normally

If the low pressure warning signal activates while you are driving, it is important that you safely exit the roadway as soon as possible and park your vehicle. If the air pressure gets too low, the brakes will no longer work well enough for you to stop safely.

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