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Based on official Illinois exam questions

Free Illinois CDL Air Brakes Test 2025

  • Perfect for first-time and renewal CDL/CLP applicants, and those adding endorsements.

Planning to drive commercial motor vehicles (CMVs) equipped with air brakes? Our practice materials are the perfect tool to prepare you for the DMV tests. Without passing, your CDL will include the restriction “L,” indicating you’re prohibited from operating CMVs with air brakes. Since semi-trucks and tractor-trailers are typically equipped with air brakes, obtaining this endorsement is essential. In fact, in Illinois, the air brakes qualification is a requirement of most companies due to the commonality of this braking system. From the flat plains of southern Illinois to the urban interchanges around Chicago and the icy winter conditions on major highways, air brake qualification is key to safety and control.

Industries across the Prairie State rely on drivers with the air brake qualification. Logistics and freight companies, charter bus services, school transportation, agriculture, manufacturing, and warehousing are just a few that require this. Schneider National, J.B. Hunt, and FedEx Freight all use vehicles equipped with air brakes. Intercity bus services like Greyhound and Megabus rely on drivers with the qualification. Additionally, regional groups like Windy City Limousine (in Chicago) and school districts are on the list because their vehicles are outfitted with air brakes. In the agriculture sector, air brakes are needed for the transport of corn, soybeans, and livestock. Likewise, the manufacturing and warehousing industries need the qualification for jobs with Caterpillar and Amazon. Simply put, the “L” restriction makes operating CMVs equipped with air brakes illegal, thus limiting your job prospects.

The official two-part DMV test covers the parts of an air brake system, effective operation, and air-brake inspection procedures. The skills test requires you to physically inspect an air brake system, identify its components, and operate a vehicle equipped with air brakes. This test includes checking air pressure, testing the brakes for leaks, and more. The multiple-choice written test requires a score of at least 80% to pass and features questions directly from material found in the state’s CDL manual.

Our Illinois CDL Air Brakes Practice Tests take into consideration all that is required for the official DMV knowledge test and mimic the content and format you will face on the test. Our practice test questions and answers provide responses in real time so you can learn quickly and be confident of passing your official exam.

9 min to complete
Available in EN and ES
IL commercial driver's license
Real exam-style pitfalls you’ll practice:
Common Traps
Distractors
Trick Wording
Double Negatives

Authored and curated by Steven Litvintchouk, M.S.

Chief Educational Researcher (ACES member)
Methodology & Editorial Policy
Last verified for accuracy: November 2025 (reviewed weekly)

What to expect on the actual IL permit test

25

questions

20

correct answers to pass

80%

passing score

More IL CDL test resources

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