Truck & Car Guides / Trucking life & careers
CDL classes A, B and C explained
What each commercial driver's license class lets you drive, how the weight thresholds work, and the general steps to get one in the US.
What a CDL is
A commercial driver's license (CDL) is required in the US to drive certain large or specialized vehicles in commerce. States issue CDLs, but the minimum standards come from federal rules overseen by the FMCSA. Since 1992, a driver may hold only one CDL, from their state of residence.
The three classes
| Class | General definition | Typical vehicles |
|---|---|---|
| A | Any combination with a gross combination weight rating of 26,001 lb or more, where the towed vehicle(s) are rated over 10,000 lb | Tractor-trailers, truck and trailer combos, many flatbeds and tankers |
| B | A single vehicle rated 26,001 lb or more, or such a vehicle towing a trailer rated 10,000 lb or less | Straight trucks, box trucks, dump trucks, city buses, garbage trucks |
| C | Vehicles that do not meet A or B but carry 16 or more people including the driver, or carry placarded hazardous materials | Smaller passenger vans and buses, small hazmat vehicles |
The classes are cumulative downward: a Class A holder can generally drive Class B and C vehicles too, as long as they have the right endorsements (for example, passenger or school bus).
Who needs one
You generally need a CDL if you drive a commercial vehicle that meets one of the definitions above. Common exceptions in federal rules include farmers in certain situations, firefighting and emergency vehicles, military drivers and recreational vehicles for personal use, but states vary. Always confirm with your state licensing agency.
Age rules
- 18: the general minimum for a CDL used only within your state (intrastate).
- 21: the general minimum to drive across state lines (interstate) or to haul placarded hazardous materials.
The general steps
- Get a DOT medical card. A certified medical examiner checks vision, hearing, blood pressure and other conditions.
- Pass knowledge tests for your class (general knowledge, combination vehicles, air brakes and any endorsements).
- Receive a Commercial Learner's Permit (CLP). You must hold it for at least 14 days before the skills test.
- Complete Entry-Level Driver Training (ELDT). Since February 7, 2022, first-time Class A and B applicants, and those adding certain endorsements, must complete theory and behind-the-wheel training from a provider listed on the FMCSA Training Provider Registry.
- Take the skills test: a pre-trip vehicle inspection, basic control skills (backing maneuvers) and an on-road drive.
- Get your CDL with any endorsements and restrictions.
Your state's CDL manual is free and is the source of most knowledge test questions. Read the sections for your class plus air brakes and combination vehicles before you pay for practice tests.
Restrictions to know
Some test choices add restrictions:
- E: no manual transmission (tested in an automatic or automated manual).
- L: no air brakes (tested in a vehicle without full air brakes).
- Z: no full air brakes (tested with air-over-hydraulic brakes).
- O: no tractor-trailer with a fifth wheel (Class A test taken in a different combination).
See CDL endorsements and restrictions.
Ways to train
- Private CDL schools: typically several weeks, paid upfront or financed.
- Carrier-sponsored training: the carrier pays or reimburses in exchange for a work commitment. Read the contract carefully, including what you owe if you leave early.
- Community colleges: sometimes cheaper, with longer programs.
After you get it
Your CDL comes with ongoing obligations: renewing your medical card, keeping a clean driving record, and following drug and alcohol testing rules. Serious violations, even in your personal car, can disqualify a CDL. Carriers also check the FMCSA Drug and Alcohol Clearinghouse before hiring.
Licensing rules are summarized in general terms and change over time. Check the FMCSA and your state DMV for current requirements.
