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 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
Passing Score
1. The ____ are activated by an electric switch that is triggered by the brake pedal.
Explanation
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?
Explanation
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:
Explanation
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:
Explanation
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:
Explanation
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.
Explanation
