Drivers who operate the specialized CMVs listed below must pass additional tests and obtain endorsements on their CDLs.
- T—Double/triple trailers (knowledge test only)
- P—Passenger (knowledge and skills tests)
- N—Tank vehicle (knowledge test only)
- H—Hazardous materials (knowledge test only)
- X—Hazardous materials and for tank and HM combination
- S—School Bus (knowledge and skills test)
See 49 CFR 383.93 about endorsements.