What 383.91A means in plain language
You were cited under 383.91A because you were operating a commercial motor vehicle that required a specific endorsement on your CDL—such as hazmat (H), tanker (N), school bus (S), passenger (P), or doubles/triples (T)—but your license did not have that endorsement.
This is different from not having a CDL at all. You hold a valid CDL, but it's missing the specialized authorization for the type of cargo or vehicle configuration you were operating. For example, pulling a tanker trailer requires a tank vehicle (N) endorsement; hauling hazardous materials requires a hazmat (H) endorsement. Operating without the correct endorsement is a strict liability violation—your intent does not matter.
What our enforcement data actually shows
Across our 13 million+ roadside inspection records, we have documented 327 all-time citations for 383.91A, with 208 citations in the last 12 months and 46 in the last 90 days. This code ranks #1060 out of 3,036 FMCSR codes by citation volume.
The enforcement consequence is severe. Our inspection data indicates a 96.3% out-of-service rate for this violation—you will almost certainly be placed out of service on the spot. For context, the all-FMCSR average OOS rate is only 31.4%, making this violation roughly three times more likely to result in immediate removal from service. Of 327 all-time citations in our database, 315 resulted in out-of-service placement, with only 12 receiving a warning or non-OOS citation.
This high OOS rate reflects the seriousness regulators assign to missing endorsements. Once cited, you cannot legally continue operating that vehicle until the violation is corrected—typically by obtaining the endorsement.
Who gets cited most
Over the last 180 days, citations for 383.91A have concentrated in three states: Texas (50 citations), Illinois (25 citations), and North Carolina (20 citations). The OOS rates within those states are consistent with the national pattern: Texas at 98.0%, Illinois at 92.0%, and North Carolina at 100.0%. North Carolina's zero-exception rate underscores that this violation triggers out-of-service placement across all major enforcement jurisdictions.
Our data shows fleets such as Joe's A Food Distributors Corp and Natural Resources Transportation Services LLC with 3 citations each on record. Neither pattern suggests systemic non-compliance; rather, the low citation counts across all carriers indicate that this violation is typically individual-incident driven rather than a fleet-wide problem.
How severe is this compared to similar codes
383.91A sits within the Driver Fitness category alongside several other licensing and qualification violations. To put it in perspective:
- 383.23(a)(2) (Operating a CMV with the wrong CDL class) has been cited 50,385 times and carries a 98.4% OOS rate. That code is vastly more frequent but similarly certain to trigger out-of-service action.
- 383.23A2-LCDLN (Operating a CMV without a valid CDL) shows 47,123 citations and a 98.6% OOS rate, again indicating near-universal out-of-service enforcement for class-level CDL violations.
- 391.41(a) (Physical qualification—general medical requirements) has 42,270 citations but only a 16.2% OOS rate, showing that missing an endorsement is treated far more strictly than some medical fitness violations.
The high OOS rate for 383.91A reflects that operating the wrong vehicle type without authorization is both easily verifiable and legally non-negotiable.
How to avoid it
Before you accept a load or assignment:
- Verify your CDL endorsements match the load. Pull out your license and confirm it displays all the endorsements required for the cargo and vehicle you are about to operate. If you will be hauling hazmat, you must have an H endorsement. If pulling a tanker, you need an N. No exceptions.
- Ask dispatch for endorsement requirements in writing. Do not assume you have the right endorsement because you have hauled "similar" loads before. Each type of cargo or vehicle configuration may require a different endorsement.
- Get the missing endorsement before you operate. Taking the CDL endorsement test takes a few hours at your state DMV. Operating without it costs you thousands in fines, a day or more out of service, and CSA points. The math is clear.
Before you leave the yard:
- Run a personal checklist of your CDL versus your manifest. Does your license have an H if this is hazmat? Does it have an N if this is a tanker? Does it have an S if this is a school bus? This takes 30 seconds.
- Confirm vehicle configuration matches your endorsements. If you have a tanker trailer attached but no N endorsement, you will be cited. Our data shows tanker-related equipment is cited frequently; if you see tank-type equipment on your vehicle, you must have an N endorsement.
Co-occurring violation patterns show what inspectors are finding:
When our inspection records document 383.91A, they commonly flag 383.23A2 (Operating a CMV without a CDL) in the same stop, appearing in 18 of the last 90 days' inspections. This overlap suggests some drivers are operating without any valid CDL, let alone the right endorsement. The second most common co-citation is 392.2RG (Operating a CMV while ill or fatigued), appearing in 17 shared inspections. Neither of these helps your case—avoid both by ensuring your CDL is valid, current, and properly endorsed, and never operate while fatigued.
Emergency equipment violations also co-occur (393.9 and 393.95A in 14 and 8 shared inspections respectively). While those are vehicle issues, they suggest that drivers cited for missing endorsements are often operating poorly maintained or non-compliant vehicles. A comprehensive pre-trip will catch both problems.
The bottom line: A missing CDL endorsement is one of the fastest routes to an out-of-service citation in the FMCSR catalog. Our data shows a 96.3% OOS rate across 327 citations. Verify your endorsements match your load before you leave, and if you do not have the endorsement, do not operate that vehicle. The cost of getting it is trivial compared to the cost of enforcement.