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It's a practice test that's automatically made up of all your missed questions. Once you finish this test, you’ll be able to revisit your Challenge Bank™ to practice and sharpen your skills.
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View All PlansThe Exam Simulator mimics the actual exam. It will stop once you reach the maximum number of allowed mistakes.
Air brakes are commonly found on large trucks and buses. They use compressed air to apply pressure to the brake shoes or pads, allowing your vehicle to come to a stop within a safe distance. Your Commercial Driver’s License (CDL) must authorize you to operate vehicles with air brakes, and that’s why you must fully understand how they work.
To operate vehicles equipped with air brakes, you must pass the air brakes knowledge test as well as a skills test in a vehicle equipped with air brakes. Both tests evaluate your knowledge of how this system works, how to inspect your brakes and how to detect brake failure. If you haven’t done so, you will be issued a CDL with a restriction code meaning “No air brake equipped vehicles.”
In Oregon, the written knowledge test is based on the official 2025 CDL manual (https://driving-tests.org/oregon/or-cdl-handbook/). Students can use this handbook to familiarize themselves with what it takes to become a commercial driver, but there are other useful resources available for those who are willing to master this subject.
Our Air Brake practice tests give you the opportunity to learn, evaluate your knowledge and identify your mistakes. Consisting of 20 questions, each practice test closely reflects the official written exam. The lack of a timer takes away the pressure of a countdown, allowing students to take as much time as they need before they submit an answer. Read every question twice and analyze each answer before submitting it, so you can fully understand the subject at hand.
A useful feature is immediate feedback, which is provided after each question. You don’t have to wait until the test is over to know which questions you got wrong. The system shows the correct answer and displays a comprehensive explanation, allowing you to identify your mistake and memorize the correct answer while also understanding its meaning.
Pro tip: Use our detailed guides on the Air Brake endorsement and the Air Brake written test to boost your learning journey. Open these guides while you are practicing on our Air Brake practice tests so you can identify the correct answer and associate it with its respective question.
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Last verified for accuracy: November 2025 (reviewed weekly)
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The Exam Simulator mimics the actual exam. It will stop once you reach the maximum number of allowed mistakes.
