CDL Air Brakes Practice Test

Practice the full Air Brakes question set for the CDL knowledge test. The written tests follow the federal model used in every state, so this one national set is the practice bank for all states. Every question comes with an instant explanation and its manual topic, so you learn the rule behind the answer instead of memorizing letters.

Free and unlimited. Every answer is explained, and your progress is saved only in your browser — no account needed.

How it works

Answer one question at a time. You will see immediately whether you were right, plus a short explanation and the manual topic for every question. At the end you get your score and can re-drill only the questions you missed.

250 questions · Topics: Dual Air Brake System & Components, Air Compressor, Governor & Reservoirs, Safety Valve & Low-Pressure Warning, Leakage Rate Standards & Air Tests, Spring Brakes, Parking & Emergency Brakes, Brake Inspection Steps & Defects, Slack Adjusters & Pushrod Stroke, Brake Fade, Heat & Downgrade Braking, ABS & Anti-Skid, Air Tank Draining, Alcohol Evaporators & Dryers, Tractor Protection Valve, Trailer Brakes & Stab Braking.

About this practice test

This set drills the Air Brakes topics from the official CDL manual: dual air brake system & components, air compressor, governor & reservoirs, safety valve & low-pressure warning, leakage rate standards & air tests, spring brakes, parking & emergency brakes, brake inspection steps & defects, slack adjusters & pushrod stroke, brake fade, heat & downgrade braking, abs & anti-skid, air tank draining, alcohol evaporators & dryers, tractor protection valve, trailer brakes & stab braking. The written tests are administered by your state licensing agency and follow the federal model used in every state; your state’s fees, scheduling and manual link are summarized on its state page.

When this set feels easy, switch to the Exam Simulator for a timed, no-feedback run, or review with flashcards.

Frequently asked questions

How many questions are on the Air Brakes test?

The Air Brakes test is typically about 25 multiple-choice questions in most states.

What score do I need to pass?

States require about 80% correct on CDL knowledge tests under the federal model. Confirm the current rule in your state’s official manual.

Are these the actual test questions?

No. These are original practice questions written from the same public manual topics the real test covers. They are designed to teach the material, not to reproduce the exam.