§383.91 establishes the three CDL classes by vehicle group: Class A for combination vehicles with a GCWR of 26,001+ lb and a towed unit over 10,000 lb; Class B for single vehicles 26,001+ lb (or any such combination where the towed unit does not exceed 10,000 lb); Class C for vehicles below the A/B thresholds that carry 16+ passengers (including the driver) or transport placardable quantities of hazardous materials. The carrier may not knowingly allow a driver to operate a vehicle outside the driver's class.
Severity weight
Severity weight 3 in the Driver Fitness BASIC. Wrong-class operation is also a §383.37 prohibition for the carrier — letting a Class B driver operate a Class A combination is a §390.5 carrier-side citation with separate exposure.
Common findings
- Class B holder pulling a trailer that crosses the 10,000 lb mark, requiring Class A.
- Class A or B without the §383.93 passenger endorsement on a CMV designed for 16+ passengers.
- Non-CDL driver assigned to a CMV that requires a CDL after a fleet change — §391.11 disqualifies on its face.
How to prevent it
- Match the driver's CDL class to the actual vehicle in dispatch — not just the typical vehicle.
- When the fleet adds a heavier vehicle, re-check every driver's class before assignment.
- Track endorsements separately (see §383.93); a CDL class is necessary but not always sufficient.
How Roadworthy HQ helps
Roadworthy HQ stores the CDL class and endorsements as discrete items, surfaces a mismatch at dispatch time against the assigned vehicle, and retains the §391.51 CDL copy with renewal tracking.