Overview
A commercial driver's license (CDL) is the US licence needed to drive large trucks, buses and vehicles that carry hazardous materials. There is no single national exam body. The federal rules in 49 CFR Part 383 set the minimum standards, and each state licensing agency gives the tests and issues the licence. Test dates, fees, test locations and the exact question counts therefore differ by state. Check your own state's driver licensing agency for those.
This page covers the federal minimum standards as printed in the eCFR when it was read in October 2026.
Who can apply
To get a commercial learner's permit (CLP), the first step, you must be at least 18 and prove your age. You must also:
pass the general knowledge test for the vehicle group you expect to drive;
certify that you are not disqualified from driving a commercial vehicle and hold a licence from no more than one state;
prove citizenship or lawful permanent residency, or qualify for a non-domiciled permit;
prove that the state you apply in is your state of domicile.
Vehicle groups
The regulation defines three groups. Pass the tests in one group and you may drive vehicles in lower groups, if you hold any endorsements needed.
| Group | Covers |
|---|---|
| A, combination vehicles | Combinations rated at 26,001 pounds or more where the towed unit is rated above 10,000 pounds |
| B, heavy straight vehicles | A single vehicle rated at 26,001 pounds or more, or one towing a unit of 10,000 pounds or less |
| C, small vehicles | Vehicles that fit neither A nor B but carry 16 or more people including the driver, or carry hazardous materials |
Exam pattern
The CDL has three parts: knowledge tests, a skills test, and extra tests for endorsements.
Knowledge tests. Each test is passed by answering at least 80 percent correctly. Failing the air brake part still lets you get a licence, but with an air brake restriction. Failing the combination vehicle part means you cannot get a Group A licence or permit.
Skills test. You take it in a representative vehicle of the group you want. It has three areas:
Pre-trip inspection: identify safety-related parts and explain what you would check, with extra air brake checks if the vehicle has air brakes.
Basic vehicle control: starting, stopping, moving forward and back, turning, shifting and backing along a straight and curved path.
On-road driving: observation, signalling, speed, gaps, turning position, following distance and weather adjustments.
Breaking traffic laws or causing a crash during the test is an automatic fail. Simulators may be used but cannot replace on-street testing.
Endorsements
| Endorsement | Required tests |
|---|---|
| Doubles and triples trailers | Knowledge |
| Passenger (P) | Knowledge and skills |
| Tank vehicle (N) | Knowledge |
| Hazardous materials (H) | Knowledge |
| School bus (S) | Knowledge and skills |
On a CLP, only the passenger, school bus and tank vehicle endorsements are allowed.
Restrictions
Where you take the skills test affects your licence. Testing in a vehicle without air brakes puts an air brake restriction on the licence, and testing in one with air-over-hydraulic brakes puts a full air brake restriction on it. Testing in an automatic vehicle puts a manual transmission restriction on it.
How to apply
Get a CLP from your state by passing the knowledge tests. A CLP is valid for no more than one year without retaking the knowledge tests.
Complete the required entry-level driver training before your first Class A or B skills test, your first passenger or school bus endorsement skills test, or your first hazardous materials knowledge test. The training must come from a provider on the federal Training Provider Registry.
Wait at least 14 days after the CLP is issued before taking the skills test.
Pass the skills test, then collect your CDL.
A CLP is a precondition for the first CDL. Holding a CLP also lets you practise on public roads in a commercial vehicle, but only with a qualified CDL holder beside you.
Preparation tips
Read your state's CDL manual, which is based on the federal knowledge requirements.
Practise the pre-trip inspection spoken aloud, in order, until it is routine.
If you want to drive vehicles with air brakes or a manual gearbox, do the skills test in such a vehicle to avoid restrictions.
Is the CDL test the same in every state?
The federal standards are the minimum. States run the tests and can add content, so the manual, fees and test sites differ by state.
What score do I need on the knowledge test?
At least 80 percent on each knowledge test.
Can I take the skills test right after getting my permit?
No. The CLP holder must wait 14 days from the issue date before taking the skills test.