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What Is a CDL 
(Commercial Driver’s License)?

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A commercial driver’s license (CDL) allows someone to legally drive many large trucks and other vehicles that require specialized skills, knowledge, and physical abilities to operate. Vehicles that require a CDL driver include tractor trailers, hazardous materials vehicles, buses, livestock trailers, and many other transport or work vehicles.

Not all work vehicles necessarily require CDLs to drive. This includes, but isn't limited to, fire trucks and law enforcement vehicles, farm vehicles, or standard USPS mail delivery trucks. However, requirements are different based on your state and specific vehicle used.


The FMCSA defines 3 different classes of CDL, depending on what definition the CMV meets:


Class A:

Any combination vehicle with a Gross Vehicle Weight Rating (GVWR) of 26,001 lbs or more, with the vehicle being towed weighing more than 10,000 lbs.


Class B:

Any single vehicle with a GVWR of more than 26,001 lbs., or combination vehicle as such towing less than 10,000 lbs.


Class C:

Any single or combination vehicle that is not classified under either Class A or B, but is designed to carry either placarded hazardous materials or 16 or more passengers, including the driver.


​More Info on the Different Classes of CDL.

Drivers operating emergency response vehicles or snow and ice removal vehicles are generally exempt from needing a CDL. Most military drivers are also exempt from the requirements, with the exception of the U.S. Reserve.

Operators of farm vehicles that meet certain criteria do not need a CDL. They must be driving a vehicle specifically used for farming, not be driving for a carrier, and stay within 150 miles of their farm.

Types of Jobs You Can Do With CDL Training

There are three primary types of CDLs, all of which allow you to drive different vehicle types: CDL Class A, CDL Class B, and CDL Class C.

While the exact definitions vary by state—and some states offer additional types of licenses—the following are typical definitions of Class A, B, and C commercial driver’s licenses.


CDL A Truck Driving License

Class A CDLs are the most flexible or universal type of CDL. With a Class A CDL, you can drive most types of vehicles covered by CDLs B and C, and you're also able to drive vehicles with two or more axles. With a CDL A, you can drive vehicles that tow a weight of over 10,000 pounds and have a combined gross vehicle weight rating (GVWR) of 26,001 pounds or more.


Vehicles covered under CDL A include:

  • Tractor-trailers (semis, big rigs, and 18-wheelers)

  • Truck and trailer combinations

  • Flatbed trucks

  • Large dump trucks

  • Livestock carriers

  • Tankers (note that hauling certain types of materials in a tanker will require endorsements to your CDL A)

CDL B Truck Driving License

CDL B licenses allow you to drive smaller vehicles—those weighing less than 26,000 pounds combined and towing less than 10,000 pounds. You can also operate most vehicles in Class C, but not Class A.


Vehicles allowed under CDL B include:

  • Straight trucks

  • Delivery/box trucks

  • School, city, tourist, and other similar buses

  • Smaller dump trucks

CDL C Truck Driving License

CDL C licenses allow you to drive the smallest vehicles that require CDLs, including any that transport 16 or more passengers (including the driver)—such as passenger vans—and hazardous materials vehicles, with the proper endorsements on your license.


Adding Endorsements to Your CDL

Specific CDL trucking endorsement requirements and availability vary by state. You can generally declare your intended endorsement when you begin your training, though you can also add one through additional training and exams later.


Some of the Most Common Endorsements include:

  • H:    Hazardous materials vehicles.

  • N:    Tank vehicles transporting liquids.

  • P:    Passenger vehicles with a specific number of passengers allowed.

  • S:    School buses.

  • T:    Double or triple trailers (semis with multiple trailers attached).

  • X:    Hazardous materials transported in tanks.


Requirements for Entering a CDL Training Program

Before applying for a CDL training program, you need to make sure you're able to earn your license in the first place.


Requirements for license in most states include:

  • Being at least 18 years old for intrastate transit and 21 for interstate transit

  • Having a valid noncommercial driver's license (you'll also generally need a CDL learner's permit)

  • Possessing a clean criminal and traffic record. You don’t need a spotless record, but felonies, DUIs, and major traffic incidents may disqualify you. A human trafficking conviction is an automatic disqualifier. Discuss your history with your school of choice to see if you're eligible before enrollment—don't worry about being judged; they've likely heard it all.

  • Willingness to be drug tested

  • Completing and being granted clearance by a physical exam

  • Having U.S. citizenship or permanent residency

  • Providing a report about your previous 10 years as a driver

Medical Conditions and Getting a CDL

There are many medical conditions that may disqualify you from getting a CDL. Some of these are automatic disqualifications, while others can be overridden after a physical examination. A few are nationwide, while others vary by state.

If you have one or more of these medical conditions (or any other medical concern that may impact your ability to drive),


Discuss the issue with your truck driving school before enrolling:

  • Anything that can result in loss of consciousness

  • Diabetes

  • Epilepsy or seizure disorders

  • Hearing loss

  • High blood pressure

  • Marijuana use, including CBD oil, even with a prescription

  • Proteinuria

  • Respiratory conditions

  • Some heart conditions

  • Vertigo or balance disorders or diseases

  • Vision loss (must be at least 20/40 with or without corrective lenses)

Site Map


  Government Websites:


  A Guide to Getting Started


  Truck Driving Schools

  Truck Driving Jobs

  Get In the Game


  Surviving The First Year


  A Few Tips For Owner Operators


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