CDL Requirements: Classes, Endorsements, and What You Need to Verify

A CDL seems straightforward — until you realize there are three classes, a half-dozen endorsements, and a bunch of restrictions that can catch drivers (and carriers) off guard. As an employer, you need to verify more than just "does this person have a CDL."

CDL Classes

Class A — Combination vehicles with a GCWR of 26,001+ lbs, where the towed vehicle exceeds 10,000 lbs. This covers tractor-trailers, truck and trailer combinations, and most flatbed setups.

Class B — Single vehicles with a GVWR of 26,001+ lbs, or such a vehicle towing a trailer under 10,000 lbs. Think straight trucks, buses, dump trucks.

Class C — Vehicles that don't meet Class A or B criteria but are designed for 16+ passengers or carry placarded hazmat. Less common in freight, more common in passenger operations.

Key Endorsements

• H — Hazmat: Required for hauling placarded hazardous materials. Requires a TSA background check that takes 60-90 days to process. Plan ahead.
• N — Tank Vehicle: For liquid or gas cargo in tanks of 119+ gallons. Combined with H, you get an "X" endorsement.
• P — Passenger: For vehicles designed to carry 16+ passengers.
• T — Doubles/Triples: Required to pull double or triple trailers.
• S — School Bus: Self-explanatory.

Common Restrictions

• L — Air Brake Restriction: Driver tested in a vehicle without air brakes. Can't operate vehicles with full air brakes. This one gets missed — make sure your drivers don't have the L restriction if your trucks have air brakes.
• E — Automatic Transmission Only: Driver tested in an automatic. Can't drive a manual.
• O — No Tractor-Trailer: Class A obtained without testing in a tractor-trailer combination.
• Z — No Full Air Brake Equipped CMV: Can operate air-over-hydraulic but not full air.

What Carriers Must Verify

Every time you hire a driver, check:

1. CDL class matches the vehicle they'll operate
2. All required endorsements are present (especially H/N for tank or hazmat)
3. No restrictions that conflict with the assignment (L restriction + air brake trucks = problem)
4. CDL is not expired, suspended, or revoked
5. The CDL state matches their state of domicile

Keep a copy of both sides of the CDL in the DQF. Check it against the MVR annually. Drivers sometimes get restrictions added or endorsements removed — and they don't always tell you.