What 393.93B means in plain language
FMCSR 393.93B requires that every truck be equipped with functional seatbelts. This is a basic safety requirement—inspectors verify that your vehicle has the correct number of seatbelts installed in the cab, that they are in working condition, and that they can be properly fastened and secured.
When you receive a citation for 393.93B, it means an inspector found one or more seatbelts missing, broken, or non-functional during a roadside inspection. This is distinct from failing to wear a seatbelt while driving (which is a different violation). The equipment itself must be present and operational on the truck.
What our enforcement data actually shows
Across our database of 13 million+ real roadside inspection records, we have documented 525 citations for 393.93B all-time, with 336 citations in the last 12 months and 62 in the last 90 days. This code ranks #900 out of 3,036 FMCSR codes by total citation volume.
The out-of-service rate for 393.93B is exceptionally low: only 0.2% of citations resulted in an out-of-service order. This means just 1 truck out of 525 cited for this violation was placed out of service. By comparison, the average FMCSR violation carries a 31.4% out-of-service rate, making 393.93B one of the least likely violations to result in immediate removal from service. In practical terms, if you are cited for missing or defective seatbelts, inspectors typically issue a citation and allow you to continue your run, though you will need to fix the problem.
Monthly citation trends over the last 12 months show variability between 8 and 44 citations per month, with a spike in October 2025 (44 citations) and relatively lower volume in April 2025 (8 citations). Most months cluster between 20 and 40 citations.
Who gets cited most
Our data shows that Texas accounts for the overwhelming majority of 393.93B citations: 138 citations in the last 180 days, with a 0.7% out-of-service rate. Iowa and Illinois each had 2 citations during the same period, both with a 0% out-of-service rate. New Mexico recorded 1 citation with no out-of-service outcome.
The geographic concentration in Texas reflects both the state's high volume of truck traffic and inspection activity. The out-of-service rate across these top states remains consistently low, indicating that seatbelt deficiencies are rarely severe enough to warrant immediate vehicle removal.
How severe is this compared to similar codes
Within the Vehicle Maintenance category, seatbelt citations are significantly less commonly cited and less likely to be out-of-serviced than many related violations. For comparison:
- 393.9 (Inoperable Required Lamp) has 180,097 all-time citations with a 6.9% out-of-service rate. Lighting defects are far more frequently cited and more likely to result in OOS orders.
- 393.78 (Windshield condition defective) has 157,894 all-time citations with a 0.3% out-of-service rate. Like 393.93B, windshield defects rarely result in OOS, but they are cited much more frequently.
- 396.3(a)(1) (Inspection/repair/maintenance – general) carries 236,919 citations and a 45.3% out-of-service rate, meaning general maintenance violations are far more serious in enforcement terms.
The low citation volume and minimal out-of-service rate for 393.93B suggest that seatbelt equipment is less frequently defective than lighting or windshield issues, and when found defective, inspectors view it as a correctable, non-critical item.
How to avoid it
Based on co-occurring violations in the same inspections, we see that 393.93B frequently appears alongside other cab-related defects. Here is what you should check during your pre-trip inspection:
- Inspect all seatbelts in the cab before each shift. Pull each belt to ensure it retracts smoothly, the latch mechanism clicks securely, and the webbing is intact (not frayed, torn, or deteriorated). If a seatbelt is jammed, sluggish, or won't stay fastened, report it for immediate repair.
- Check seatbelt anchor points and hardware. Look at the bolts and brackets that attach the seatbelt assembly to the frame. Loose, missing, or rusted fasteners can compromise seatbelt function. Tighten or replace as needed.
- Do not postpone seatbelt repairs. Unlike some components that may have a grace period, seatbelt deficiencies are straightforward to fix and inexpensive. A trip to a truck service center or a quick hardware repair prevents a citation and improves cab safety.
- Correlate with cab condition checks. Our data shows 393.93B co-occurs with windshield defects (393.78), inoperable lamps (393.9), and defrost/defog failures (393.79). When you inspect seatbelts, also verify your cab lighting, wipers, and defroster function to avoid multiple citations in one stop.
- For fleet managers: Track seatbelt repair completion in your maintenance records. Since seatbelts are low-cost and quick to replace, ensure your shops prioritize them in routine services. Audit cab safety items (seatbelts, lighting, glass) as a bundle in pre-trip checklists to catch clusters of defects early.
The consistent enforcement pattern and the minimal out-of-service consequence indicate that this violation is preventable through basic pre-trip discipline. A 30-second seatbelt check before departing can eliminate citation risk entirely.