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Missouri Air Brakes Test

We'll help you master air brakes before you hit I-70 through the Ozarks.

118
Questions
80%
To Pass
30
Minutes

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

Opens in a practice window — choose your mode inside.

JM

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

Last verified: August 2026

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

About the Missouri Air Brakes Test

Missouri's highways demand skilled air brake operation. You'll haul crops from the Bootheel to grain elevators in the north. Winter ice on I-44 near Rolla can make stopping a challenge. Our practice test prepares you for these real conditions.

Air brakes are mandatory for most commercial vehicles in Missouri. The written exam tests your knowledge of system components, emergency procedures, and inspection steps. Don't let a failing score delay your CDL.

We built this test from the official Missouri CDL handbook. Each question reflects what the DMV examiner expects. Practice until you score 80% or higher.

Missouri's steep grades on US-60 through the Ozarks require controlled braking. Know your slack adjusters and brake lag. This test covers it all.

Topics Covered

✓Air brake system components – crucial for Missouri's cold winters when moisture can freeze in lines.
✓Dual air brake systems – required for any truck on I-70's high-speed stretches.
✓Brake lag and stopping distance – vital on Missouri's wet roads from spring storms.
✓Emergency braking procedures – used when deer cross US-63 at night.
✓Foundation brakes vs. spring brakes – Missouri inspectors check these during roadside inspections.
✓Daily air brake inspection – a must before hauling livestock from Missouri feedlots.

Study Tips

Missouri's DMV offers the air brakes test at all driver examination stations. You'll need an appointment at most locations. Study the CDL handbook sections 4 and 5. Practice with our test until you can pass without hesitation.

Focus on brake adjustment indicators. The Missouri road test requires you to check slack adjusters. Know the difference between yellow and red knobs. That's a common trick question.

Don't skip the pre-trip inspection portion. Missouri examiners watch for proper air brake checks. They'll ask about low pressure warnings and governor cut-out. Our test covers those details.

Missouri Specific Information

You can take the air brakes written test at any Missouri State Highway Patrol driver examination station. Popular sites include St. Louis, Kansas City, Springfield, and Jefferson City. Appointments are recommended – walk-ins face long waits. The test fee is $10 per attempt, payable by cash or card.

After passing the written test, you'll receive a CLP. The air brakes endorsement costs $5 extra. You must pass both the written and skills test within 180 days. Check mo.gov for real-time appointment openings.

Some rural stations close for lunch. Bring a snack if you're testing in places like West Plains or Kennett. Arrive early to avoid missing your slot.

Frequently Asked Questions

Do I need a separate air brakes endorsement for a Class B CDL in Missouri?
Yes, if your vehicle has air brakes. The endorsement is the same for Class A and B. You'll take the same written test.
Can I take the Missouri air brakes test online?
No. You must take it in person at a driver examination station. No online option exists for the written CDL test in Missouri.
What happens if I fail the air brakes test in Missouri?
You can retake it the same day at some locations. Most stations require a 24-hour wait. You'll pay the $10 fee each time.
Is the air brakes endorsement required for farm vehicles in Missouri?
Not always. Farm plate trucks with air brakes still need the endorsement unless exempt. Check the Missouri CDL handbook for exemptions.
How many questions are on the Missouri air brakes test?
The test has 25 questions. You need 20 correct to pass. That's 80%.
JM

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

Last verified: August 2026 · FMCSA-compliant content