Since April 1, 1992, when this Act became law, all drivers have been required to have a CDL in order to drive a Commercial Motor Vehicle. The Federal Highway Administration (FHWA) has developed testing standards for licensing drivers. U.S. states are able to issue CDLs only after a written and practical test have been given by the State or approved testing facility.

A driver needs a CDL if the vehicle meets one of the following definitions of a CMV:

• Class A truck – Any combination of vehicles with a GVWR of 26,001 or more pounds (11,793 kg) provided the GVWR of the vehicle(s) being towed is in excess of 10,000 pounds (4536 kg).
• Class B truck – Any single vehicle with a GVWR of 26,001 or more pounds (11,793 kg), or any such vehicle towing a vehicle not in excess of 10,000 pounds (4536 kg) GVWR.
• Class C truck – Any single vehicle, or combination of vehicles, that does not meet the definition of Class A or Class B, but is either designed to transport 16 or more passengers, including the driver, or is placarded for hazardous materials.
• Endorsements
  • T – Double / Triple Trailers – a knowledge test
  • P – Passenger – knowledge and skills test
  • N – Tank Vehicle – a knowledge test
  • H – Hazardous Material – a knowledge test
  • S – School Bus – knowledge and skills test
  • X – Hazmat / Tanker Combination

The minimum age to apply for a CDL is usually 21, as required by the United States Department of Transportation, although some states allow drivers who are 18 to 20 to apply for a CDL that is valid only within the driver’s state of residence. A single state CDL only restricts driving of CMVs within the holder’s state (not non-commercial vehicles), and automatically converts to a 50 state CDL at the age of 21.