- 0 Incorrect (6 allowed to pass)
- 0 Correct
- Updated for February 2025
- Based on 2025 OR commercial driver's license manual
Free Oregon CDL Air Brakes Test 2025
You have come to the right place for a sure-fire method of passing your Oregon DMV CDL Air Brakes Knowledge Test on your first attempt. Without passing the knowledge test, your CDL will include the restriction “L,” preventing you from operating commercial motor vehicles (CMVs) with air brakes. Securing a CDL without this restriction is vital for expanded job opportunities in Oregon because most semi-trucks and tractor-trailers rely on air brakes. Failing the air brakes test in Oregon results in a one-day waiting period and a retest fee should you decide to retake the test. Use our Oregon DMV CDL Air Brakes Practice Tests to pass on the first attempt.
The steep grades, sharp curves, and elevation changes in the Cascade Mountains, the coastal range, and the high desert areas demand air brakes for brake reliability. The wintry mountain passes are especially challenging and need air brake-qualified drivers. Key transportation routes include I-5 (connecting Portland, Salem, and Eugene), I-84 (winding through the Columbia River Gorge), US-26 (major east-west route), and OR-58 (with its steep descents and curves, particularly near Willamette Pass). As most semi-trucks and tractor-trailers rely on air brakes, restriction “L” would severely limit your job opportunities.
The Beaver State relies on drivers with the air brake qualification in key industries, including timber and logging (one of the largest lumber producers in the U.S.), agriculture, and technology and manufacturing (Intel and Nike). Other major companies requiring this qualification include Schneider National (Portland), Old Dominion Freight Line, FedEx, and UPS as well as TriMet (Portland), Greyhound, and FlixBus in the public transit and charter bus industries. School districts across Oregon also employ thousands of full-size school bus drivers and require the air brake qualification.
Our CDL Air Brakes Practice Tests cover everything needed for the official DMV Air Brakes Knowledge Test. What you learn will also help you practice inspecting and operating CMVs to pass your skills test. The written Air Brakes knowledge test features multiple-choice questions based on the state’s CDL manual (Oregon CDL Handbook 2025) and requires a score of at least 80% to pass.
Our Practice Tests mimic the official knowledge test and offer real-time feedback on all responses. This scientifically proven approach helps you learn faster and ensures you pass the test.
- Perfect for first-time and renewal CDL/CLP applicants, and those adding endorsements
- Triple-checked for accuracy
What you need to know
What to expect on the actual OR DMV exam
questions
correct answers to pass
passing score
List of questions (classic view)
- Which of the following is NOT part of the air brake system?
- At what measurement is the safety valve USUALLY set to open?
- When should you drain your air tanks?
- Spring brakes are
- Which of the following are true about a dual air brake system?
- Which of the following can cause brakes to fade or fail?
- The purpose of a supply pressure gauge is
- How can you tell if your vehicle is equipped with an antilock braking system (ABS)?
- What is the best way to test if your vehicle's spring brakes come on automatically?
- How would you check your truck's slack adjusters?
- If the air tanks are not drained,
- How do brakes work on a long, steep downgrade?
- Under which conditions are front wheel brakes good?
- The tractor protection valve
- An antilock braking system (ABS)
- Slack adjusters are
- When should you use the parking brake?
- Why must you pass a knowledge test on air brakes?
- 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)?
- Which of the following is NOT part of the drum brake?
- Which vehicles must have low air pressure warning signals?
- What is the best way to test your vehicle's low air pressure warning signal?
- Which of the following will be true about your brake function if your antilock braking system (ABS) fails?
- Which of the following should you do before leaving your vehicle unattended?
- After the initial drop, the maximum acceptable leakage rates per minute are
- The low air pressure warning signal will come on before the pressure in the air tanks falls below
- A low pressure warning signal is required on
- All vehicles equipped with air brakes have
- With air brake-equipped vehicles, the parking brakes should be used
- The use of air brakes on a downgrade is only a supplement to the
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Here's an inside look at how we maintain the highest quality in our practice tests.
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- Alignment with Official Manuals:
Every question we develop is based on the most recent version of each state's official driving manual. Our team regularly monitors each state DMV's website for the latest updates to ensure our practice tests are always aligned with the most current information. - Community Feedback Integration:
We leverage feedback from our vast community of users to understand which topics are most frequently tested. This helps us focus on the areas that are most relevant and beneficial for your preparation. - Expert Content Creation:
Our in-house editor, Steven, who has extensive experience in driver education, crafts each question with precision. He conducts a thorough review of each question against the official manuals to ensure accuracy. - Rigorous Review Process:
Once Steven has finalized a set of questions, our team conducts a joint review session. This second level of scrutiny involves content accuracy, proofreading, and fact-checking to eliminate any errors. - User Feedback Mechanism:
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In line with our commitment to accuracy, we quickly update our practice questions to reflect any changes in the DMV manuals. Additionally, we update the free electronic copy of the state's driver's license manuals on our site, typically within a few days after the DMV publishes them.
Our thorough quality control process ensures that you have access to practice tests that are as accurate and up-to-date as possible. We believe in the power of well-prepared drivers and are dedicated to providing you with the best study tools to help you succeed on your DMV exam.
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