T Endorsement: Allows you to tow a double or triple trailer.See our guide to passenger and school bus endorsements. ALSO requires separate application forms, fees, and background checks.S Endorsement: Permits the operation of a school bus.Requires written knowledge AND road skills tests.P Endorsement: Allows you to operate a vehicle that carries over a specified number of passengers (the exact number may depend on your state).Requires an additional written knowledge test.N Endorsement: Permits you to operate tank vehicles.H Endorsement: Required for vehicles containing hazardous materials.In either case, additional testing and fees will be required.Īfter you have satisfied the requirements for a Class A, B, or C commercial driver's license, you may also need to pass additional written and road driving tests to operate special types of commercial motor vehicles.īelow is a list of the federal endorsement codes you may need in addition to your CDL and what tests will be required by your state. In order to drive certain types of vehicles with a commercial driver's license (CDL), it may be necessary to add an endorsement or remove a restriction.