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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 Delaware CDL knowledge test. The DE 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 Delaware CDL Manual. Take this DE CDL practice test now to prepare for the actual air brakes test!
1. If the air tanks are not drained:
the air pressure in the tanks is reduced.
the spring brakes will come on.
the water can freeze in cold weather and cause brake failure.
your speed must be reduced to 5 MPH below your “safe” speed.
2. Tar in the road pavement rising to the road surface in very hot weather:
might get in your engine.
causes the road to become very slippery.
does not affect the road surface or driving conditions.
is very sticky and will slow down your vehicle.
3. If you are being tailgated, you should:
turn on your taillights.
try to let the other vehicle pass.
speed up.
drive on the shoulder.
4. Foundation brakes are used:
only with the rear wheels.
at each wheel.
only with the right wheels.
only with the front wheels.
5. When driving in a construction zone, if a construction worker is near the road, you should:
speed up.
come to a complete stop.
maintain a constant speed.
further reduce your speed.
6. The application pressure gauge shows:
how much pressure is in the air tanks.
how much air pressure you are applying to the brakes.
how much pressure the relay valves should send to the trailer brakes.
All of the above.
7. The best way to know what's going on behind and to the sides of your vehicle is to:
use the rear view camera.
lean out of the window.
check your mirrors regularly.
ask your passenger(s).
8. When driving a 60 foot truck at 35 mph in ideal conditions, you should keep at least _______ of space in front of you.
12 seconds
6 seconds
4 seconds
5 seconds
9. Having ABS on only the trailer:
makes the trailer more likely to roll over.
still gives you more control over your vehicle during braking.
makes the trailer more likely to swing out.
is very dangerous.
10. Most heavy-duty vehicles use:
solid brakes.
hydraulic brakes.
air brakes.
pressure brakes.
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DE Air Brakes Test

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