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  • Updated for February 2025
  • Based on 2025 OH commercial driver's license manual

Free Ohio CDL Air Brakes Test 2025

Failure to pass the Ohio BMV CDL Air Brakes Knowledge Test means that your CDL will include the restriction “L,” preventing you from operating commercial motor vehicles (CMVs) with air brakes. You will see shortly that this “L” restriction is significantly damaging to your job prospects in this market. Failing the air brakes test in Ohio results in a one-day waiting period and a fee should you decide to retake the test. Our Ohio BMV CDL Air Brakes Practice Tests are your key to passing your knowledge exam on the first attempt.

From the downgrades of the Appalachian foothills and the winds on the flat plains to the rolling hills in central Ohio, powerful, reliable braking is necessary for safe navigation. Winter storms and urban traffic present challenges that require air brake-qualified drivers. Key transportation routes include I-70 (a major east-west route connecting Columbus to Dayton), I-71 (linking Cincinnati, Columbus, and Cleveland), I-75 (a major north-south corridor from Michigan to Florida), and the Ohio Turnpike (I-80/I-90). Because most semi-trucks, tractor-trailers, and commercial buses rely on air brakes for safe navigation, removing the air brake restriction from your CDL is vital for expanded job opportunities.

The Buckeye State relies on drivers with the air brake qualification in key industries, including automotive manufacturing, logistics and freight, and agriculture. Companies requiring the air brake qualification include Honda (Marysville) and Procter & Gamble (Cincinnati) in the manufacturing industry, as well as FedEx Freight, XPO Logistics, and R&L Carriers in the logistics sector. Barons Bus Lines (Cleveland) and Lakefront Lines (Columbus and Cleveland) are major charter bus companies that require air brakes. Additionally, Ohio school districts use air brakes on their full-size buses, employing hundreds of air brake-qualified drivers. The “L” restriction makes these jobs unattainable.

The written Air Brakes knowledge test features multiple-choice questions based on the state’s CDL manual (Ohio CDL Handbook 2025) and requires a score of at least 80% to pass. Our CDL Air Brakes Practice Tests cover everything needed for the official BMV Air Brakes Knowledge Test. As a bonus, the information you learn will also be useful as you prepare to pass your skills test.

You’ll receive instant feedback on all our Practice Test responses, and our tests mimic the official knowledge test. This proven approach helps you learn faster and ensures you pass the knowledge test!

  • 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 OH BMV exam

25

questions

20

correct answers to pass

80%

passing score

List of questions (classic view)

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