A commercial driver's license (CDL) is a driver's license required in the United States to operate large and heavy vehicles (including trucks, buses, and trailers) or a vehicle of any size that transports hazardous materials or more than 15 passengers (including the driver). United States In the United States, the Commercial Motor Vehicle Safety Act of 1986 established minimum requirements that must be met when a state issues a CDL. While recreational vehicles and farm vehicles are exempt from requiring a CDL, federal law allows states to require a CDL for these vehicles. However, such vehicles are federally exempt from having to obtain a CDL. The following types of CDL licenses are: Class A – Any combination of vehicles that has a gross combination weight rating or gross combination weight of 26,001 pounds (11,794 kilograms) or more inclusive of a towed unit(s) with a gross vehicle weight rating or gross vehicle weight of more than 10,000 pounds (4,536 kilograms). Class B – Any single vehicle which has a gross vehicle weight rating or gross vehicle weight of 26,001 pounds (11,794 kilograms) or more, or any such vehicle towing a vehicle with a gross vehicle weight rating or gross vehicle weight that does not exceed 10,000 pounds (4,536 kilograms). Class C – 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 transporting material that has been designated as hazardous under 49 U.S.C. 5103 and is required to be placarded under subpart F of 49 CFR Part 172 or is transporting any quantity of a material listed as a select agent or toxin in 42 CFR Part 73. Age requirements The minimum age for a CDL is determined by state governments. All states, as well as the District of Columbia, have made 18 the minimum age for a CDL to be issued with the exception of Hawaii where the minimum age is 21. The Federal Motor Carrier Safety Administration (FMCSA) requires drivers to be 21 years or over to drive a commercial vehicle in interstate commerce (to move goods across state lines) and transport hazardous materials when placards are required. The FMCSA allows states to issue a CDL to drivers under 21 providing they only drive a commercial vehicle within the state where the CDL was issued,