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CDL A Versus CDL B

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A commercial driver's license (CDL) is required to drive commercial vehicles. The primary difference between a CDL A and a CDL B is the weight of the vehicles a person is allowed to drive. Understand that additional endorsements may be required to operate specific types of commercial vehicles. For example, an "H" endorsement is for hazardous materials. An "S" endorsement is for school buses.


Commercial motor vehicles (CMV) are large pieces of heavy transportation equipment. Buses, trucks, semis, trailers and construction equipment are examples of commercial vehicles. Depending on the size of the vehicle, a specific commercial driver's license (CDL) is required. Currently, there are three types of CDL classes: A, B or C.

Class A

Class A drivers are allowed to drive a commercial vehicle with trailer. The trailer must weigh more than 10,000 lbs. Together, the weight for both the commercial vehicle and trailer must exceed more than 26,001 lbs. when fully loaded. An example of a commercial vehicle requiring a Class A license is a large semi with a trailer of goods that exceeds the 10,000-lb. weight limit when loaded.

Class B

Class B licenses refer to CMVs with a gross weight of at least 26,001 lbs. that may tow trailers. For this license, the gross trailer weight must be less than 10,000 lbs. when fully loaded. Examples of vehicles that require a Class B license are tow trucks, garbage trucks, water trucks, cement mixers and some buses. Vehicles that do not meet this weight restriction fall into Class C requirements.

Driver Requirements

Class A and Class B drivers are granted a license after successfully passing a written examination and behind-the-wheel test. Check with your state to see what minimum age requirements for driving are. Some states issue CDLs to drivers as young as 18 with a restriction to stay within state borders. Drivers must be 21 to cross border lines. All drivers must be in good physical condition, subject to vision testing, physical examination and medical history requirements. Employers also conduct random drug and alcohol testing.


If a driver has had a CDL suspended or revoked in another state, the application is rejected. Drivers with commercial driver's licenses are not allowed to have any other license and must use the CDL as their only proof of license. A career in transportation is demanding physically and emotionally. Remember that some drivers are away from their homes and families for days, if not weeks, at a time.