Tennessee Air Brakes Test

About the Tennessee Air Brakes Test

Air brakes aren't optional in Tennessee—they're mandatory for most commercial trucks. Our state's terrain makes them critical. You've got the Mississippi River flats in the west, then rolling hills through Middle Tennessee, and finally the steep mountain grades in east Tennessee near the Smokies. That I-24 Monteagle Mountain stretch? It drops 1,200 feet in just 6 miles. If your brakes fail there, you're in serious trouble.

Tennessee's weather adds another layer. Summer heat can cause brake fade on long descents. Winter ice and rain reduce traction when you need to stop. And don't forget the humidity—it speeds up corrosion in air tanks. You'll need to drain those tanks every day, especially if you're running through Memphis or Nashville where the air gets thick.

Our practice test covers everything Tennessee examiners look for. Slack adjusters, brake lag, low pressure warnings—we hit it all. Each question comes straight from the Tennessee CDL manual. You'll see real-world scenarios like pulling a loaded gravel trailer down I-40 near Cookeville or stopping a tanker on wet I-65. No fluff. Just the stuff that matters.

Take this test a few times. When you score 80% or higher, you'll be ready for the real thing. We keep it up to date with Tennessee's latest rules. No surprises on exam day.

What This Test Covers

• Brake system components – you'll need to identify parts for Tennessee's pre-trip inspection, including the air compressor and governor
• Dual air brake systems – understand both primary and secondary circuits for safe operation on I-40's long grades
• Air brake emergency stops – practice stopping distances on wet roads, common during Tennessee's spring storms
• Low pressure warnings – know the 60 PSI threshold for the warning light, critical before descending Monteagle Mountain
• Slack adjusters and brake lag – adjust them correctly to pass Tennessee's brake inspection at weigh stations
• Air tank draining – drain daily to remove moisture from Tennessee's humid climate, especially in summer

Study Tips

Start with the Tennessee CDL Handbook. Focus on the air brakes chapter—pages 25 through 40 cover everything for your endorsement. Then use our practice test. Take it at least three times. Miss a question? Look it up in the handbook right away. That's how you lock it in.

Book your appointment online at your local Tennessee DMV. They're busy, so schedule two weeks out. Walk-in slots fill fast, especially in Nashville and Chattanooga. Bring your CLP (Commercial Learner Permit) and pay the $30 fee. The air brakes test is usually 25 multiple-choice questions. You get 30 minutes. Don't rush—but don't take all day either. Answer what you know first, then go back. You'll pass.

Tennessee DMV Information

You can take the air brakes knowledge test at any Tennessee Driver Service Center that offers CDL services. Major locations include Nashville (Hart Lane), Memphis (Bishop Lane), Knoxville (Lexington Drive), and Chattanooga (Kay Street). Check the TN Department of Safety and Homeland Security website to confirm hours. Most centers open at 8:00 AM and close by 4:30 PM, but times vary.

Appointments are strongly recommended. Walk-ins are accepted but you might wait 2-3 hours. Book online at tn.gov/safety. You'll need your Tennessee CDL learner permit, a valid ID, and payment of $30 for the endorsement test (cash or card). Some locations only take debit/credit, so call ahead.

After passing the written test, get an air brakes restriction removed from your CDL. You'll also complete a skills test in a vehicle with air brakes. The skills test includes a pre-trip inspection of the air system. Know how to check for audible air leaks and test the low pressure warning device. Tennessee examiners are strict—they've seen it all.

Frequently Asked Questions

Related Resources

Other Tennessee CDL Practice Tests

Test Details

• State: Tennessee
• Test: Air Brakes Test
• Questions: 118
• Passing Score: 80%
• Time Limit: 30 minutes
• Cost: Free

Need ELDT Training?

If you're getting your first CDL, you need ELDT theory training before your skills test.