There are a total of 6 commercial endorsements and 1 restriction for the commercial driver license (CDL). Each endorsement or restriction requires the commercial driver to pass specific tests.
| Endorsement/Restriction | Description |
|---|---|
| Passenger endorsement (P) | Required for all drivers of vehicles designed to carry 16 or more persons (including the driver). |
| School bus endorsement (S) | Required for drivers who operate school buses to transport students to or from school and for school sponsored events. (Note: A passenger endorsement is also required for a school bus endorsement to be valid.) |
| Double/triple trailers endorsement (T) | Required for drivers pulling sets of double or triple trailers. |
| Tank vehicle endorsement (N) | Required for drivers of vehicles carrying liquids or liquid gases in portable or fixed tanks. This endorsement is not required for portable tanks with a rated capacity under 1,000 gallons. |
| Hazardous materials endorsement (H) | Required for drivers of vehicles carrying hazardous materials that require the vehicle to be classified or placarded for hazardous materials. For a hazardous materials endorsement (HME), drivers are required to be fingerprinted and undergo a federal background check. This includes the first time you get an HME, or when you renew or transfer a license from another state. |
| Combination endorsement (X) | This is a combination of a tank and hazardous materials endorsement. |
| Air brake restriction (K) | This is an automatic restriction. If a driver has successfully passed the necessary written and driving tests for air brake equipped vehicles, this endorsement will be removed. Drivers who do not pass these tests are restricted on the CDL to non-air brake vehicles. |