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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 Colorado CDL knowledge test. The CO 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 Colorado CDL Manual. Take this CO CDL practice test now to prepare for the actual air brakes test!
1. Which of the following is NOT correct? An ABS system:
helps you avoid wheel lock up.
is a safety anti-skid braking system.
helps you stop faster.
reduces the braking pressure to a safe level.
2. The ABS malfunction lamp on the instrument panel is:
3. Air tanks usually hold enough compressed air to allow the brakes to be used _________ even if the compressor stops working.
for one stop
for one day
several times
for 3 days
4. Vehicles with air brakes require more stopping distance than vehicles with hydraulic brakes. Why?
It takes one half second or more for the air to flow through the lines to the brakes.
When driving vehicles with air brakes, the average perception distance increases from 400 feet to 2200 feet.
Stopping distance for vehicles with air brakes is made up of six different factors.
Air brakes use different brake drums.
5. An alcohol evaporator is important during:
dry weather.
windy weather.
hot weather.
cold weather.
6. After a tire has been changed, the driver should stop a short while later to:
check tread separation.
decrease tire pressure.
deflate the tire to 10 psi.
check the tightness of the nuts.
7. On any upgrade, gravity:
doubles your speed.
doesn't affect your speed.
slows you down.
speed you up.
8. On front tires, tread should be at least:
2/32 inch
1/16 inch
4/16 inch
4/32 inch
9. 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.
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.
1 psi for single vehicles and 3 psi for a combination of 2 vehicles.
10. To avoid becoming a distracted driver you should:
eat and drink while you drive.
not turn off all communication devices.
not engage in complex conversations with others.
adjust all vehicle controls and mirrors while driving.
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CO CDL Air Brakes Test

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