Take Free CDL Practice Tests
Start with inspection, air brakes and combination vehicles. Free tests open with no sign-up.
Start freePass your CDL knowledge test the first time with our CDL Practice Tests
General knowledge, air brakes and combination vehicles. Practice free, then upgrade to Premium for full exams.
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‹ All tests7/20
Air brakes
At about what pressure does the governor normally cut the compressor out?
The governor usually cuts in near 100 psi and cuts out near 125 psi. These numbers can vary slightly by vehicle.
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2026 Updated CDL Practice Tests
Built from the federal CDL manual, with every answer explained
Study for the tests you need to earn your commercial learner’s permit and your CDL. Follow the steps below for an easy pass.
Unlock the Full CDL Exams
Premium adds the general knowledge, air brakes and combination vehicles exams, and a full exam simulator.
See PremiumWalk Into the Test With Confidence
Know the numbers, the parts and the safe answer, so test day feels familiar.
The Smart Way to Prepare for Your CDL
Practice by endorsement
Take the general knowledge test, then add air brakes, combination vehicles and the endorsements you need for your truck or bus.
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Every answer explained
See why the right answer is right and why the others are not, with the pressure numbers, distances and rules that tests ask about.
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Simple and easy to use
Use it on your phone between loads, or on a computer at home. Your progress is saved when you have an account.
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Pick your CDL tests
Every driver takes general knowledge. Add the endorsements for the vehicle you want to drive.
- General knowledgePractice now
Required for every CDL. Inspection, vehicle control, hazards, cargo and the rules.
- Air brakesPractice now
Compressor, tanks, warnings and the brake checks. Needed to drive any air-braked vehicle.
- Combination vehiclesPractice now
Coupling, uncoupling, rollovers and trailer skids. Needed for Class A.
- Hazardous materialsComing soon
Placards, loading and emergencies when hauling hazmat.
- Tank vehiclesComing soon
Liquid surge, baffles and handling a partly filled tank.
- Doubles and triplesComing soon
Pulling more than one trailer safely.
- PassengerComing soon
Driving a bus with passengers aboard.
- School busComing soon
Loading zones, stops and student safety.
Which class do you need?
Class A
A combination of vehicles with a trailer over 10,000 lbs, such as a tractor-trailer.
Class B
A single heavy vehicle, such as a straight truck, dump truck or large bus.
Class C
Smaller vehicles that carry 16 or more passengers or hazardous materials.
CDL by state
The questions are the same federal set. Each state page points you to your licensing agency.
- TXTexasCDL practice
- CACaliforniaCDL practice
- FLFloridaCDL practice
- PAPennsylvaniaCDL practice
- OHOhioCDL practice
More states are on the way.
CDL Premium
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7-Day CDL Prep
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A fast, focused week before your knowledge test.
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- Full CDL exam simulator
- Every premium CDL test
- Air brakes and combination vehicle exams
- Question shuffling, different every time
- Explanations on every answer
- Ad-free practice
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30-Day CDL Prep
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A full month to learn the manual and be ready for every endorsement test.
$35 / 30 days
30 daysOne-time payment · No subscription. It never renews. Nothing to cancel.
- Full CDL exam simulator
- Every premium CDL test
- Air brakes and combination vehicle exams
- Question shuffling, different every time
- Explanations on every answer
- Ad-free practice
- Family sharing
Lifetime CDL Prep
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Study at your own pace and come back for every new endorsement.
$59 / Lifetime
LifetimeOne-time payment · No subscription. It never renews. Nothing to cancel.
- Full CDL exam simulator
- Every premium CDL test
- Air brakes and combination vehicle exams
- Question shuffling, different every time
- Explanations on every answer
- Ad-free practice
- Family sharing
Common questions
What is on the CDL knowledge test?
Every CDL applicant takes the general knowledge test. Depending on what you drive, you also take endorsement tests such as air brakes and combination vehicles. These practice tests follow the federal CDL driver manual that state tests are built on.
Do I need a permit before I take the CDL test?
Yes. You pass the knowledge tests to get a Commercial Learner's Permit (CLP). Federal rules then require you to hold the CLP for at least 14 days before the skills test.
How old do I have to be?
Federal rules set 18 for driving inside one state and 21 for driving between states or hauling hazardous materials. Your state may add its own rules, so check with your licensing agency.
Are these the real test questions?
No. They are practice questions written from the federal CDL manual, with every answer explained. Your state's own manual can add rules, so read it too and use the link to your agency on your state page.
Which endorsements can I practice today?
General knowledge, air brakes and combination vehicles are ready now. Hazardous materials, tank vehicles, doubles and triples, passenger and school bus are coming.