A Commercial Drivers License (CDL) is a federally required license that allows you to operate vehicles that requiring special knowledge. There are different levels,or classes, of CDL’s. Each allows you to drive different sizes of vehicles, and specialized equipment. After you qualify for a size of vehicle, then you must test for several endorsements. If you fail certain parts they will put limitations on your license. Here is the section from the FMCSA (The Federal Motor Carrier Safety Administration) that addresses this…
byClasses of License:The Federal standard requires States to issue a CDL to drivers according to the following license classifications:Class A — Any combination of vehicles with a Gross Combination Weight Rating (GCWR) of 26,001 or more pounds provided the gross vehicle weight rating (GVWR) of the vehicle(s) being towed is in excess of 10,000 pounds.Class B — Any single vehicle with a GVWR of 26,001 or more pounds, or any such vehicle towing a vehicle not in excess of 10,000 pounds GVWR.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.Endorsements and Restrictions:Endorsements:Drivers who operate special types of CMVs must pass additional tests to obtain any of the following endorsements placed on their CDL: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 – Combination of tank vehicle and hazardous materials endorsements
S – School Bus (Knowledge and Skills Tests)
States may have additional codes for additional grouping of endorsements, as long as such codes are fully explained on the license.Restrictions:“L” On a full air brake vehicle, if a driver fails either the air brake component of the general knowledge test, or performs the skills test in a vehicle not equipped with air brakes, then the driver will have an “L” air brake restriction placed on their license.“Z” If the driver takes the test in a vehicle with an air over hydraulic brake system, then they will have a “Z” no full air brake restriction placed on their license. In either case the driver is not authorized to operate a CMV equipped with air brakes.“E” If the driver takes the Skills Test in a vehicle that has an automatic transmission, then an “E” no manual transmission restriction is placed on their license.“O” If the driver takes the Skills Test in a Class A vehicle that has a pintle hook or other non-fifth wheel connection, they will have an ”O” restriction placed on their license restricting them from driving any Class A vehicle with a fifth wheel connection.“M” If a driver possesses a Class A CDL, but obtains his or her passenger or school bus endorsement in a Class B vehicle the State must place an “M” restriction indicating that the driver can only operate Class B and C passenger vehicle or school buses.“N” If a driver possesses a Class B CDL, but obtains his or her passenger or school bus endorsement in a Class C vehicle; the State must place an “N” restriction indicating that the driver can only operate Class C passenger vehicle or school buses.