§393.93 requires that the driver's seat in every CMV manufactured on or after January 1, 1965, be equipped with a Type 1 (lap) or Type 2 (lap and shoulder) seat belt assembly meeting FMVSS 209. Other designated seating positions are addressed in §393.93(c). The seat itself must be secured to the floor or chassis with anchorages meeting §393.93(d) strength requirements.
Severity weight + OOS
Severity weight 4 in the Vehicle Maintenance BASIC. A driver's seat belt that is missing, cut, frayed through, anchored incorrectly, or non-functional is an out-of-service condition — the driver cannot legally operate without it. Compare to §392.16 (driver failing to wear the belt that is present), which is a separate Unsafe Driving cite.
How it gets cited
The patterns are physical condition (cut webbing, sun-damaged webbing that has lost tensile strength), missing retractor function (belt does not retract or lock), and anchorage damage (a bolt has pulled through the floor pan, the buckle frame is fatigued). The §393.93 cite is the equipment finding; the §392.16 cite is the behavioral one.
How to prevent it
- Inspect seat belt condition on every pre-trip — webbing, retractor lock, buckle latch.
- Replace seat belts on a maintenance schedule for older vehicles — UV degrades webbing on a clock that runs even when the belt sits unused.
- Verify seat anchorages at every §396.17 annual inspection; pulled anchorages from collision damage are easy to miss.
How Roadworthy HQ helps
A seat or seat-belt equipment citation shows up in Roadworthy HQ as part of the inspection it came from, not as a record of its own: the app does not store individual violation codes. Log the roadside inspection on the vehicle's Inspections tab: date, state, level, driver, the number of violations, and whether it was out-of-service. For an out-of-service inspection the 15-day §396.9(d)(3) repair-certification countdown stays on that tab until you enter the certification date. The rule's 15 days cover every violation on the report, not only out-of-service ones, so for a non-OOS inspection that date is yours to track. The repair itself goes in the vehicle's maintenance log: date, type, what was done, who did it, and cost. DVIRs are logged per vehicle with the defect described in your own words, and a defect marked safety-affecting that is logged without a repair certification sends a critical alert.