All your missed questions are saved
automatically for extra practice.
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.
View All PlansAdding difficult questions to Challenge Bank™ is an exclusive Premium feature. Unlock access to 650+ exam-like questions, a Pass Guarantee, personalized study plans, and more.
View All Plans| 90-100 | => | 7% |
| 80-89 | => | 29% |
| 70-79 | => | 21% |
| 60-69 | => | 7% |
| <60% | => | 36% |
A Missouri Commercial Driver’s License (CDL) can qualify you for many exciting driving opportunities, but the “L” restriction excludes you from some of the best ones. The “L” restriction prohibits you from driving vehicles equipped with air brakes. Since most semi-trucks, tractor-trailers, and full-size buses are equipped with air brakes, it is advantageous for you to have extensive knowledge of their operation. Otherwise, you may be passing up positions with employers, such as Hogan Transportation and Prime, Inc., offering higher salaries and great benefits. Many municipalities, such as Jefferson City, also need air brake-qualified drivers to operate the buses in their public transportation system. Air brakes help you slow down to navigate sharp turns and stop in heavy traffic, and it is important for you to be familiar with their operation.
Chief Educational Researcher, Driving‑Tests.org (ACES member)
Last verified for accuracy on
Our Missouri DOR CDL air brake “endorsement” practice test will introduce you to an efficient study method that teaches you about air brake systems. Before the air brake restriction can be removed from your CDL, you must pass a skills test in a vehicle with air brakes (including conducting an inspection of the air brakes) and pass an official Air Brakes knowledge test. You must correctly answer at least 80% of the 25 questions on the official knowledge test to receive a passing score.
This Missouri DOR CDL air brake “endorsement” practice test will provide you with comprehensive instruction designed to eliminate your learning barriers. The practice test uses 30 questions, similar to those on the official knowledge test, to gauge your current understanding of air brakes and help you identify the information most crucial for enhancing it. The practice test gives you a detailed plan to achieve your goals.
The practice test is based on the most recent Missouri DOR CDL manual (Missouri CDL Handbook 2025) and is up to date as of December 2025. If you submit an incorrect answer, the practice test will provide a complete explanation of the correction, using information taken directly from the CDL manual. You can confidently apply this information to various driving situations on the official knowledge test because it comes from the most authoritative source available.
If you’ve tried traditional study methods, you’ll find the practice test is more effective in helping you gain a deep understanding of air brakes. Traditional study methods are designed to be one-dimensional by training you to memorize the answers to the questions and forcing you to search for the information to correct the answers you get wrong. The practice test makes the most confusing topics understandable using reliable information presented in easily understood language.
Chuck Berry became the Father of Rock ‘n’ Roll by creating a distinctive musical sound, and you can develop distinguished driving skills using the practice tests at https://driving-tests.org/missouri/.
Driver’s Ed is - nobody wants to set foot inside the DOR. That’s why millions of learners trust us for simple, visual, effective prep.
We are an officially recognized FMCSA Entry-Level Driver Training provider and a proud partner to over 2,500 libraries. We work with safety organizations like GHSA and the National Safety Council to help create safer roads for everyone.
Our trademarked system automatically saves questions you miss, creating personalized tests that target your weak spots until you’ve mastered the material.
Get smarter as you study. Our new AI-powered feedback provides detailed, question-level insights to help you understand the why behind each answer.
Go beyond the boring black-and-white manual. Our interactive handbook lets you read, listen with an MP3 audio version, or even chat with it to find the information you need, faster.
We build our practice questions from the current 2025 MO Driver Handbook and refine them using patterns recent test‑takers report.
Driver handbook • Knowledge‑test/permit overview • Fees & ID requirements • Office/appointment info
We mirror recurring themes (e.g., right‑of‑way traps, sign look‑alikes) and use similar distractors and wording styles.
We don’t collect or publish actual test items and we’re not affiliated with DOR.
