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Illinois Air Brakes Test

You'll navigate icy patches on I-55—this test prepares you for that.

118

Questions

80%

To Pass

Minutes

118 questions · 30 min time limit · 80% to pass

Opens in a practice window — choose your mode inside.

Reviewed by Jack Mahana, CDL Instructor (13+ years)

Last verified: August 2026

All questions sourced from the official Illinois CDL handbook and FMCSA regulations.

About the Illinois Air Brakes Test

Illinois drivers haul freight through Chicago's congested expressways and across flat farmland. You'll need to handle air brakes on I-55, I-57, and I-80. Our winters bring snow and ice—air brake knowledge keeps you safe.

This practice test covers everything from brake lag to emergency stops. Each question mirrors what you'll see at the Illinois Secretary of State facility. You don't get second chances on road tests, so prepare now.

Illinois inspectors look for brake adjustment during your pre-trip. They watch how you drain air tanks and check low pressure warning. Our test builds those habits before you sit in the driver's seat.

Topics Covered

✓Air brake components – you'll inspect them before every trip on Illinois roads.

✓Brake lag – critical on Illinois's long, straight highways where stopping distance matters.

✓Emergency braking – essential for avoiding deer on rural Illinois routes.

✓Low air pressure warning – Illinois winters make system leaks more common.

✓Spring brakes – know how they work; Illinois examiners test this during pre-trip.

✓Dual air systems – Illinois requires separate systems for safety; understand the setup.

Study Tips

Study the Illinois CDL handbook's air brake section. Focus on pre-trip inspection steps—Illinois examiners check your brake inspection thoroughly. Practice with our test to identify weak spots.

Watch videos of air brake components in action. Many Illinois CDL students learn faster by seeing diaphragm chambers and slack adjusters move. Repeat the practice test until you score 90% or higher.

Illinois Specific Information

Visit any Illinois DMV (Secretary of State facility) with a CDL testing center. Schedule your appointment online at ilsos.gov. Fee is $60 for the air brakes endorsement. Bring your valid driver's license and social security card.

Testing locations include Chicago West, Schaumburg, Springfield, and others. Arrive 15 minutes early. If you fail, you can retake the written test after one business day. No appointment needed for retakes—just walk in.

Frequently Asked Questions

Do I need an air brakes endorsement in Illinois?

Yes—if your vehicle has air brakes, you need the restriction removed. You'll take a 25-question written test. Pass it, and you can drive any air-brake equipped commercial vehicle in Illinois.

What's the passing score for the Illinois air brakes test?

80% — that's 20 correct out of 25. Miss 5, and you fail. You can retake the next business day.

Does the Illinois air brakes test include a pre-trip demonstration?

Yes, during your road test. The examiner watches you check the air brake system. You'll point out components and do a full inspection. Study the pre-trip steps from the Illinois CDL manual.

Can I take the air brakes endorsement test online in Illinois?

No. You must visit an Illinois Secretary of State facility that offers CDL testing. No online options exist yet. Schedule an appointment to save time.

How long does the Illinois air brakes written test take?

About 30 minutes. You'll get 25 multiple-choice questions. Most people finish in 15-20 minutes. Take your time—there's no rush.

Reviewed by Jack Mahana, CDL Instructor (13+ years)

Last verified: August 2026 · FMCSA-compliant content