What is a Commercial Driver’s License?

A quick guide to CDL classifications*

Have you ever wondered “what is a CDL?” A Commercial Driver’s License (CDL) is a license specific to operating heavy, oversized vehicles and those that carry multiple passengers. Fact: every truck driver on the road today needs to have some type of CDL. So, whether you see yourself as a long-haul trucker, a school bus driver or piloting the motor coach for a rock band, you’ll first need the right Commercial Driver’s License for the job. A Commercial Driver’s License falls into one of three categories. 

Class A CDL 

  • For any combination of vehicles with a gross combination weight rating (GCWR) of 26,001 lbs. or more
  • This is inclusive of a towed unit(s) with a gross vehicle weight rating (GVWR) of more than 10,000 lbs.
  • With a Class A CDL, you may be able to drive these vehicles:

- Tractor-trailers

- Truck and trailer combinations (double and triple trailers)

- Tractor-trailer buses

- Tanker vehicles

- Livestock carriers

- Flatbeds

Class B CDL

  • For any single vehicle with a GVWR of 26,001 lbs. or more
  • If towing, the GVWR of the vehicle being towed may not exceed 10,000 lbs.
  • With a Class B CDL, you may be able to drive these vehicles:

- Straight trucks

- Large buses, including:

• City buses

• Tourist buses

- School buses

- Segmented buses

- Box trucks, such as:

• Delivery drivers

• Couriers

• Furniture delivery

- Dump trucks with small trailers

Class C CDL

  • Some single and combination vehicles are designed to transport specific quantities of passengers or materials that may be considered dangerous and may not meet other CDL classifications. Class C Commercial Driver’s Licenses cover vehicles which: 
  1. Carry 16+ passengers, including the driver
  2. Transport material designated as hazardous, as described by federal guidelines
  • With a Class C CDL, you may be able to drive these vehicles:

- Small HAZMAT vehicles

- Passenger vans

- Small truck towing a trailer


Now that you have a better understanding of CDL classifications, let’s explore endorsements. In addition to your Class A CDL, Class B CDL or Class C CDL, you may need to take additional written or road tests to be qualified to operate special types of vehicles that your job requires. This could include safely transporting hazardous materials, towing more than one trailer or operating a school bus. Click here to explore a full list of available endorsements.


Here are some examples of restrictions that might impose special requirements on drivers seeking a Commercial Driver’s License. For example, a driver may be prohibited from operating a manual transmission if the skills test was performed on a vehicle with an automatic transmission. Other restrictions include the following: 

B – Corrective lenses

C – Mechanical aid

D – Prosthetic aid

E – Automatic transmission only

F – Dual outside mirror

G – Daylight only operation

K – CDL intrastate only

L – Vehicles without air brakes

M – Group B or Group C passenger vehicles

N – Group C passenger vehicles only

O – No fifth wheel (combination vehicles)

P – Commercial Learner's Permit Only. No passengers other than trainer, additional trainees or test examiner 

U – Hearing aide required

V – Medical variance required

W – Medical waiver required

X – Commercial Learner's Permit Only. No cargo in tank vehicle and tank must be purged. Restricts "N" endorsement

Z – No full air brake-equipped commercial motor vehicle

* Are you still asking yourself “what is a CDL?” The information on this page is intended to provide an overview, since requirements vary by state. For a deeper dive into, CDL classifications, more information about earning a Commercial Driver’s License in your State and necessary medical certifications, visit the CDL.com State Requirements page or FMCSA site for more information.