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AIR BRAKES CDL PRACTICE TEST - DISTRICT OF COLUMBIA

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The air brakes endorsement applies to applicants who wish to drive a vehicle with air brakes in Class A, B, or C CDL. To drive a vehicle with air brakes, you must pass the air brake component of the District of Columbia CDL knowledge test. The DC CDL air brakes test consists of 25 questions, and you'll need at least 20 correct answers to pass (80%). The test covers the information found in the air brakes section of the District of Columbia CDL Manual. Take this DC CDL practice test now to prepare for the actual air brakes test!
1. When the low air pressure warning light and buzzer first come on, you should:
downshift and slow down.
bring the vehicle to a safe stop right away.
speed up to restore pressure.
immediately put alcohol into the air system.
2. To perform an applied leakage test, the vehicle’s air pressure should be built up to maximum pressure. Check the air gauge to see that the air pressure should drop no more than:
2 psi for single vehicles and 5 psi for a combination of 2 vehicles.
1 psi for single vehicles and 3 psi for a combination of 2 vehicles.
5 psi for single vehicles and 6 psi for a combination of 2 vehicles.
3 psi for single vehicles and 4 psi for a combination of 2 vehicles.
3. Air tanks must be drained because:
if one air system is low on pressure, the rear brakes will not be operating fully.
compressed air usually has some water in it. The water can freeze in cold weather and cause brake failure.
when you push the brake pedal, air is let into each brake chamber.
if you don't drain the tanks yourself, your battery fluid may drain out.
4. If your vehicle is hydroplaning, you should:
accelerate to get through the water as quickly as possible.
use the brakes to slow down.
release the accelerator and push in the clutch.
None of the above.
5. Which of the following is NOT a warning sign of fatigue?
Trouble remembering the last few miles driven
Frequent blinking
Driving at the speed of the traffic
Heavy eyelids
6. The parking or emergency brakes of trucks or buses must be held on by:
spring pressure.
fluid pressure.
hydraulic pressure.
air pressure.
7. On a tractor-trailer equipped with a trailer brake hand valve, the hand valve can be used to:
prevent movement of cargo.
hold compressed air.
keep from rolling back.
reduce the chance of the front wheels skidding.
8. With a fully-charged air system, the maximum leakage rates are:
5 psi for single vehicles and 10 psi for a combination of two vehicles.
5 psi for single vehicles and 4 psi for a combination of two vehicles.
2 psi for single vehicles and 3 psi for a combination of two vehicles.
3 psi for single vehicles and 4 psi for a combination of two vehicles.
9. A low air pressure warning signal:
is required on vehicles with air brakes.
is required on all vehicles without air brakes.
is optional on vehicles with air brakes.
None of the above.
10. If your vehicle has dual parking control valves, you can use pressure from a separate tank to:
park better.
balance the service brakes while you are parked.
release the spring brakes so you can move the vehicle in an emergency.
None of the above.
 
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DC Air Brakes Test

Number of questions: 25
Correct answers to pass:20
Passing score:80%
Number of questions: 25
Correct answers to pass:20
Passing score:80%
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