CDL Exam – Air Brakes Endorsement

The Commercial Driver’s licensing (CDL), Air Brakes endorsement is required for any Commercial Motor Vehicle (CMV) driver who operates a vehicle with air brakes. The Commercial Motor Vehicle Safety Act of 1986 establishes the knowledge and skills required to ensure drivers of trucks and buses with air brakes are qualified operators. The Air Brake endorsement test is not required if your CMV does not have air brakes. However, if you do not take, or fail the air brake endorsement test, a restriction is placed on your license. It is cost-effective to take the air brake endorsement with the general knowledge and skills test.

The registration process, cost, and location

To register for the air brake endorsement, visit your local license office. Most states include the cost of the endorsement with their written test fee. If you are applying for your first CDL, the air brake endorsement test fee is included with your initial application. If you are adding the endorsement to your CDL, fees vary by state and range from $5.00 to $56.00. Check with your state’s licensing office to confirm the cost of the endorsement.

Most states conduct the endorsement test at the local office. Some states utilize an authorized test center to administer the test. If your state uses a test center, an additional fee for the facility could be imposed.

Test design

The air brake endorsement test contains two parts – written and practical.

The written test is administered by computer and consists of 20 to 25 multiple-choice questions. Some states use a 20-question test (Florida, for example) and some states use a 25-question test (Alabama, for example). The passing grade for the written exam is 80%. On a 25-question test, you can miss five questions. On a 20-question test, you can miss four questions. Often the air brake test is added to the general knowledge exam for first-time CDL drivers.

While the general information is standardized throughout the United States, each state creates its test and focuses on different information on the written exam. The basic content of the written exam includes components of an air brake system, dual air brakes, proper inspection of the air brake system, and the safe use of air brakes. Check with your local office for content specific to your state.

The practical exam is included in the skills test for first-time CDL drivers. If you are adding the endorsement to your CDL, you will have to schedule the skills test through your licensing office. The road test ensures you are able to drive a vehicle with air brakes safely. During the road test, your skill at using air brakes in different situations is evaluated. Some tasks that you are evaluated on include:

  • Building air pressure
  • Releasing brakes
  • Using the air brakes and the appropriate pressure for different tasks
  • Testing low air
  • Air pressure gauge

The passing score for the air brake endorsement is included with the road test if you are taking the CDL test for the first time. To pass just the endorsement, you will need to demonstrate your knowledge with as few mistakes as possible. Some states require an error-free performance; some allow less than three errors. Check with your local office for the passing requirements.


Both the written and skills exam are scored and reported to you after your exam. If you did not pass, you can retake the exam independently of one another. It is possible for you to pass the written test and not the skills test or vice-versa. Every state’s retest policy varies. Some states allow you to take the exam once every seven days, and some require a waiting period between attempts. Each state’s retest fee varies as well. Again, check with your local office for the specifics of their retesting policies.

How Can I Prepare for the CDL Test?

That’s a great question.  We’ve broken down the answer into three parts.

  1. Do yourself a favor and study.  Do not walk in unprepared. We have recommended prep materials below, but that only helps if you actually try.  Plus, studying is actually proven to be the best antidote to test anxiety.
  2. Take care of yourself.  Make sure you’re eating well, exercising, and sleeping.  All of these things are scientifically linked to brain performance.  If you take care of your body, you’ll be helping your grades.
  3. Get a study guide or set of flashcards.  Some people study better a certain way. Find your study strengths and make the most of them.  We’ve tried to make it easy for you by tracking down the best study guide and flashcard set for your exam. Below you’ll see links to both!

Study Guide



Last Updated: June 21, 2021