§383.93 lists the endorsements that may be added to a CDL: (T) double/triple trailers; (P) passenger; (S) school bus; (N) tank vehicle; (H) hazardous materials; and (X) the combined tank + hazardous materials endorsement. Each endorsement has its own knowledge-test requirement under §383.117–.123 and, for H/X, a TSA security threat assessment under 49 CFR Part 1572.
Severity weight
Severity weight 3 in the Driver Fitness BASIC. The carrier-side §383.37(a) prohibition on letting an under-endorsed driver operate makes this a two-citation event when found at roadside.
What triggers an endorsement
- Towing a second or third trailer (combination longer than one trailer): T endorsement.
- 16+ passenger capacity including the driver: P endorsement.
- Operating a school bus that meets §383.5: S endorsement (in addition to P).
- Operating a tank with a rated water capacity of 1,000+ gallons mounted on a CMV: N endorsement (note: §383.5 definition matters — empty tank operation still requires the endorsement).
- Placarded hazardous-materials quantities: H endorsement plus TSA STA.
How to prevent it
- Maintain a per-driver endorsement table and cross-reference at dispatch.
- TSA STA for H/X must renew every five years — track the renewal as its own date.
- New-entrant carriers entering hazmat or passenger work: re-check every driver before the new operation begins.
How Roadworthy HQ helps
The driver profile stores CDL class, endorsements, and expiration, with reminders 90, 60, 30, and 7 days before the CDL expires and an alert once it has. The CDL copy is one of the required items on the driver's DQF tab. Roadworthy HQ does not track the TSA security threat assessment date behind an H or X endorsement, and it does not check endorsements against the vehicle or commodity. Roadworthy HQ has no dispatch system, so nothing in it can stop a driver or a vehicle from being assigned a load.