CDL Class A vs Class B vs Class C: which one do you need?
The weight limits that define each class, which vehicles they cover, which knowledge tests each one needs, and how the restriction codes cut them down.
The three CDL classes are defined by weight ratings, not by the kind of job. Two numbers decide everything: the gross vehicle weight rating (GVWR) of a single vehicle and the gross combination weight rating (GCWR) of a truck plus whatever it tows. The dividing line is 26,001 pounds.
The three classes
| Class | Definition | Typical vehicles | Knowledge tests |
|---|---|---|---|
| A | Combination with a GCWR of 26,001 lb or more, towing a unit rated over 10,000 lb | Tractor-trailers, truck and trailer combinations, tanker rigs, livestock carriers, flatbeds | General knowledge, combination vehicles, air brakes |
| B | Single vehicle with a GVWR of 26,001 lb or more, or such a vehicle towing a trailer rated 10,000 lb or less | Straight trucks, dump trucks, box trucks, cement mixers, city and tour buses, large school buses | General knowledge, air brakes |
| C | Vehicle that does not meet A or B but carries 16 or more people including the driver, or placarded hazardous materials | Small shuttle buses, passenger vans, small hazmat trucks | General knowledge plus passenger or hazmat |
A Class A licence lets you drive Class B and C vehicles too, as long as you hold the endorsements those vehicles need. Class B covers Class C vehicles the same way. The classes nest downwards, never upwards.
Reading the weight ratings
The ratings are the manufacturer's maximums, printed on the vehicle's certification label, not what the truck happens to weigh today. An empty tractor pulling an empty 53-foot trailer is still a Class A combination because the ratings are over the line. That is also why a pickup towing a heavy gooseneck trailer can need a Class A: a 14,000 lb truck and a 14,000 lb trailer add up to a GCWR of 28,000 lb with a towed unit over 10,000 lb.
Two common edge cases:
- A truck towing a light trailer. A 33,000 lb straight truck pulling a 9,000 lb trailer stays in Class B, because the trailer is rated 10,000 lb or less.
- A heavy pickup alone. A one-ton pickup rated under 26,001 lb is not a commercial vehicle at all unless it carries 16 or more people or placarded hazmat.
Which class to go for
If you plan to drive over the road in a tractor-trailer, you need Class A, and most training schools teach to it because it opens the most jobs. Local delivery, construction, refuse and transit work is largely Class B. Class C is specialised: small passenger shuttles and small hazmat loads.
A Class A test takes more study than Class B because of the combination vehicles section, which covers coupling and uncoupling, fifth wheels, air lines between tractor and trailer, and trailer rollover. The combination vehicles practice test covers it.
Restrictions that narrow a class
The letter on your licence can be cut down by restriction codes, set at the skills test:
- L: no vehicles with full air brakes, because you skipped the air brakes knowledge test or tested in a vehicle without them.
- Z: no full air brakes, because you tested in a vehicle with air-over-hydraulic brakes.
- E: no manual transmission, because you tested in an automatic.
- O: no tractor-trailers, because you took the Class A test in a combination joined by a pintle hook rather than a fifth wheel.
- M and N: a Class A or B holder limited to smaller passenger vehicles than the class would otherwise allow.
- K: intrastate only, usually because the driver is under 21 or self-certified as intrastate.
The endorsements and restrictions guide lists all of them.