What 391.11B4 means in plain language
Every CDL holder is required to tell their state licensing agency which category of interstate or intrastate commerce they operate in — this is called self-certification. The categories matter because they determine what medical documentation you must carry and keep on file.
The violation captured under 391.11B4 occurs when a driver is operating a non-excepted commercial vehicle — meaning a truck or bus that requires full medical qualification — but has told their state that they fall into an excepted interstate category. Excepted interstate operations cover a narrow set of situations where federal medical certificate requirements don't apply. If you're actually hauling regulated freight or passengers across state lines under standard DOT authority, claiming that excepted status creates a mismatch between your self-certification and the work you're actually doing.
In short: your CDL record says you don't need a medical certificate on file with your state because of the category you selected, but the vehicle you're driving and the operation you're running say otherwise. That gap is exactly what 391.11B4 captures, and inspectors are trained to spot it.
What our enforcement data actually shows
This code carries one of the most aggressive out-of-service rates in the entire FMCSR rulebook. Across our 13 million+ inspection records, 391.11B4 has produced 4,026 all-time citations, with 3,827 of those resulting in an out-of-service order — a 95.1% OOS rate. To put that in perspective, the all-FMCSR average OOS rate across all codes is just 31.4%. This code runs more than three times that average.
Despite the code being officially marked as OOS-ineligible in the regulatory framework, our data makes clear that inspectors exercising their authority are placing drivers out of service at an extraordinary rate. If you've been cited, the odds were overwhelmingly against you continuing your trip that day.
Enforcement volume is also accelerating. Over the last 12 months, our inspection records show 2,684 citations for this code alone. In just the last 90 days, there were 545 citations — meaning this is not a rarely-enforced technicality. The monthly trend data shows the code generating between 198 and 271 citations per month during the stretch from January 2026 through early 2026, with a high of 271 citations in a single month. This is an active enforcement priority, ranked #384 out of 3,036 FMCSR codes by all-time citation volume.
Who gets cited most
Looking at the last 180 days, our inspection records show the heaviest enforcement concentration in three states: Texas, California, and Missouri.
Texas leads by a wide margin with 305 citations and a 99.7% OOS rate — effectively every driver stopped for this violation in Texas gets parked. California comes in second with 194 citations, with a slightly lower but still severe 93.3% OOS rate. Missouri recorded 63 citations and a 100.0% OOS rate, meaning every single driver cited there over this period was placed out of service. The variation between Iowa (70.7% OOS rate on 41 citations) and states like Missouri, New York, Georgia, Arkansas, and Ohio (all at 100.0%) shows that where you get stopped can meaningfully affect whether you drive away, though a sub-30% chance of continuing your run is not a number worth gambling on.
Among carriers in our database, even large, well-resourced fleets have accumulated citations. Our data shows fleets such as Federal Express Corporation (USDOT 86876) with 12 citations and Swift Transportation Co of Arizona LLC (USDOT 54283) with 6 citations appearing in the all-time records. Self-certification accuracy is a systemwide challenge, not just a small-carrier problem.
How severe is this compared to similar codes
Within the Driver Fitness category, 391.11B4's 95.1% OOS rate stands alongside some of the harshest codes in the FMCSR system. Consider these peers:
- 391.41APC — Operating a property-carrying vehicle without a valid medical certificate in possession or on file with the state drivers licensing agency has 49,539 all-time citations and a 97.1% OOS rate. It's one of the most-cited codes in this category and nearly always results in an OOS order — and notably, it appears in 36 shared inspections with 391.11B4 in just the last 90 days, meaning these two violations frequently travel together.
- 383.23(a)(2) — CDL wrong class has 50,385 citations and a 98.4% OOS rate. Like 391.11B4, it reflects a licensing-status mismatch between what your credentials say and what you're actually operating.
- 383.23A2-LCDLN — Operating a CMV without a valid CDL carries 47,123 citations and a 98.6% OOS rate. This code also co-occurred with 391.11B4 in 26 shared inspections over the last 90 days, underscoring how qualification-layer violations cluster together during a single inspection.
All three peer codes share one trait with 391.11B4: they reflect situations where a driver's documented qualifications don't match the operation underway, and inspectors treat these as immediate grounds to park the truck.
How to avoid it
The fix for 391.11B4 starts long before you reach the scale or weigh station — it starts with your state DMV record.
- Verify your self-certification category before every dispatch cycle. Log into your state's CDL portal and confirm that your self-certification reflects your actual operation. If you're running non-excepted interstate commerce, you need to be certified as such, with a current medical examiner's certificate on file with your state.
- Carry your medical examiner's certificate and confirm it's on file with your state. Our data shows 391.41APC — operating without a valid medical certificate on file — co-occurred with 391.11B4 in 36 shared inspections in the last 90 days. These two issues are closely linked: fix the self-certification, then verify the certificate is uploaded and current.
- Check for CDL validity issues during pre-trip. 391.11B4 showed up alongside operating without a valid CDL (383.23A2-LCDLN) in 26 shared inspections recently. If your self-certification is wrong, your CDL's medical status at the state level may already be degraded or downgraded — a status check through your state DMV takes minutes and catches this.
- Don't skip pre-trip mechanical checks because a paperwork stop seems unlikely. In 52 shared inspections over the last 90 days, 391.11B4 was cited alongside no proof of periodic inspection (396.17C-PI). In 41 cases it appeared with inoperable required lamps (393.9), and in 26 cases with defective slack adjusters (393.47E). FRHT and Freightliner vehicles account for the largest share of cited vehicles in our database — if you're running one of those platforms, a complete brake and lighting check before departure is non-negotiable. Inspectors who pull you for a certification issue will inspect the truck too.
- If you've changed your operation type, update your self-certification immediately. Drivers who shift from a local intrastate run to an interstate dedicated lane sometimes forget to update their certification category. That gap can persist for months until a roadside inspector queries your CDL record and finds the mismatch.