What Is a CDL?
Everything you need to know about the Commercial Driver's License
A CDL (Commercial Driver's License)is a special driver's license required to operate large, heavy, or hazardous material vehicles in the United States. If a vehicle weighs over 26,001 pounds, carries 16+ passengers, or transports hazardous materials, the driver must hold a CDL.
Who Needs a CDL?
You need a CDL if you plan to drive any of the following:
- Semi-trucks and tractor-trailers — the most common CDL vehicles
- Large buses — city transit, tour buses, school buses (16+ passengers)
- Tanker trucks — transporting liquids or gases in bulk
- Flatbed trucks — hauling construction equipment and oversized loads
- HAZMAT vehicles — any vehicle carrying hazardous materials
The Three CDL Classes
CDLs are divided into three classes based on vehicle weight and type:
Class A — Combination Vehicles
Tractor-trailers, truck and trailer combos, and any combination over 26,001 lbs where the trailer exceeds 10,000 lbs. This is the most versatile CDL class.
Class B — Heavy Straight Vehicles
Single vehicles over 26,001 lbs — dump trucks, large buses, delivery trucks, and cement mixers.
Class C — Small Vehicles with Special Cargo
Vehicles under 26,001 lbs that carry 16+ passengers or hazardous materials. Includes small HAZMAT vehicles and passenger vans.
Learn more about each class in our CDL Classes guide.
How Do You Get a CDL?
- Study for and pass the written knowledge tests
- Obtain your CLP (Commercial Learner's Permit)
- Practice driving with a licensed CDL holder
- Pass the CDL skills test (pre-trip inspection, basic controls, road test)
- Receive your CDL
See our complete How to Get a CDL guide for the full step-by-step process.
Start Studying Today
The written knowledge test is the first step. CDL Answers has 1,200+ practice questions covering every test section — General Knowledge, Air Brakes, HAZMAT, and all endorsements.