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  • Updated for December 2024
  • Based on 2024 CO commercial driver's license manual

Free Colorado CDL Air Brakes Test 2024

Your knowledge of air brakes will be tested with 30 multiple-choice questions that will make you more prepared for your upcoming DMV exam, and help you to become a safer driver.

Each question is based on information you can find in the Colorado Commercial Driver License Driver Manual and applicable Colorado laws. We recommend reviewing the explanation that accompanies each question so that you will be prepared to answer future questions about the material covered in this practice exam.

Good luck, practice until you feel confident, and drive safely!

Unlock full access with Premium
  • Perfect for first-time and renewal CDL/CLP applicants, and those adding endorsements

What you need to know

9 min to complete
Available in EN and ES
Verified by Steven Litvintchouk, M.S., Chief Educational Researcher, Member of ACES. See our detailed commitment to accuracy and quality in our practice tests.

What to expect on the actual CO DMV exam

25

questions

20

correct answers to pass

80%

passing score

List of questions (classic view)

  1. How would you check your truck's slack adjusters?
  2. Which of the following can cause brakes to fail or fade?
  3. Under which conditions are front wheel brakes good?
  4. When should you drain your air tanks?
  5. Which of the following should you do before leaving your vehicle unattended?
  6. Spring brakes are
  7. How do brakes work on a long, steep downgrade?
  8. The maximum leakage rates per minute after the initial drop are
  9. Why must you study air brakes in the state of Colorado?
  10. Which of the following is true about a dual air brake system?
  11. Why must air tanks be drained?
  12. The tractor protection valve
  13. Which of the following will be true about your brake function if your ABS fails?
  14. Which of the following is NOT part of the braking process when driving a tractor-trailer combination vehicle with an anti-lock braking system (ABS)?
  15. What is the best way to test your vehicle's low air pressure warning signal?
  16. Slack adjusters are
  17. What is the best way to test if your vehicle's spring brakes come on automatically?
  18. When should you use the parking brake?
  19. The purpose of a supply pressure gauge is
  20. At what measurement is the safety valve USUALLY set to open?
  21. Which vehicles must have low air pressure warning signals?
  22. How can you tell if your vehicle is equipped with an anti-lock braking system (ABS)?
  23. Which of the following is NOT part of the air brake system?
  24. Which of the following is NOT part of the drum brake?
  25. An anti-lock braking system (ABS)
  26. The low air pressure warning signal will come on before the pressure in the air tanks falls below
  27. A low pressure warning signal is required on
  28. All vehicles equipped with air brakes have
  29. With air brake-equipped vehicles, the parking brakes should be used
  30. The use of air brakes on a downgrade is only a supplement to the
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