What 391.45(b) means in plain language
Every commercial driver is required to hold a current, valid medical examiner's certificate proving they meet the physical qualification standards set for CMV operators. When that certificate lapses — even by a single day — you are technically operating without proof of current medical fitness, and that's exactly what 391.45(b) targets.
The rule exists because the medical certificate has an expiration date for a reason: your health status can change, and periodic re-examination is how the system confirms you're still fit to operate a commercial vehicle. Driving after that date has passed means you haven't had that verification, regardless of how healthy you actually feel.
The fix sounds simple — get re-examined and get a new certificate — but the citation still goes on your record, your carrier's record, and into the national inspection database the moment it's written up at the roadside.
What our enforcement data actually shows
Across our database of 13 million+ inspections, 391.45(b) has generated 9,698 all-time citations, placing it at #231 out of 3,036 FMCSR codes by citation volume. That's a meaningful number — this is not an obscure edge-case violation.
Here's the part that may surprise you: the out-of-service rate for this code is just 3.5%. Of the 9,698 citations ever recorded, only 337 drivers were actually placed out of service. The remaining 9,361 citations resulted in a written violation with no OOS order attached. For context, the all-FMCSR average OOS rate is 31.4%, meaning 391.45(b) is cited far more often than it results in a driver being shut down on the spot — its 3.5% rate is roughly nine times lower than that system-wide average.
That said, "not OOS eligible" does not mean consequence-free. The citation still counts against your driver record and feeds into your carrier's Safety Measurement System (SMS) scores.
One more important data point: our records show zero citations in the last 90 days and zero in the last 12 months for this specific code. That suggests enforcement under this exact code designation has shifted or tapered off in recent periods, even as related medical certificate violations remain heavily enforced under other code numbers.
Who gets cited most
Our inspection records don't include a state-by-state breakdown for 391.45(b) in the current data snapshot, so we won't speculate on geography. What the data does show is that citations have appeared across a wide range of fleet types and sizes.
Among carriers in our database, Keystone Automotive Industries Inc (USDOT 778752) appears with 8 citations and Compass Group USA Inc (USDOT 132504) with 7 citations — the two highest totals of any carrier for this code. Further down the list, carriers including Central Transport LLC, Federal Express Corporation, and United Parcel Service Inc each show citations in the 4–5 range. These are large, well-resourced fleets, which tells you something important: an expired medical certificate is an administrative oversight that can happen anywhere, not a symptom of a poorly run operation.
On the equipment side, Freightliner (FRHT) leads all vehicle makes with 693 citations tied to this violation, followed by Ford at 563 and International (INTL) at 316. Kenworth (KW) and Peterbilt (PTRB) round out the top five at 299 and 244 respectively. The spread across makes reinforces that this is a driver documentation issue, not a vehicle-specific problem.
How severe is this compared to similar codes
The Driver Fitness category contains some of the most aggressively enforced violations in the FMCSR system, and 391.45(b) sits at the gentler end of that spectrum.
Compare it to 391.41APC, which covers operating a property-carrying vehicle without a valid medical certificate in possession or on file with the licensing agency. That peer code has accumulated 49,539 citations — more than five times the volume of 391.45(b) — and carries a 97.1% OOS rate. Drivers cited under 391.41APC are almost always shut down on the spot.
Similarly, 383.23(a)(2), which addresses operating a CMV with the wrong CDL class, shows 50,385 citations and a 98.4% OOS rate. And 383.23A2-LCDLN, covering drivers who don't possess a valid CDL at all, has 47,123 citations at a 98.6% OOS rate.
The contrast is stark. An expired medical certificate under 391.45(b) gets written up at a 3.5% OOS rate; the closely related issue of having no certificate at all — or no valid CDL — puts you out of service nearly every single time. The difference is the paper trail: an expired certificate proves you were once medically qualified. The absence of any certificate or license is treated as an immediate disqualifier.
How to avoid it
An expired medical certificate is one of the most preventable citations in the FMCSR system. Every one of these 9,698 citations in our database was avoidable with a calendar reminder. Here's how to stay clear:
- Know your expiration date before every trip. Your medical examiner's certificate has a printed expiration date. Check it the same way you check your CDL — before you ever leave the yard. Add it to your pre-trip mental checklist.
- Set a 60-day and a 30-day reminder. Medical exams require scheduling, and examiners can be booked out. Waiting until the week before your certificate expires is a real risk. Build in enough lead time to reschedule if something falls through.
- Keep a physical and digital copy accessible. Many drivers store a photo of their current certificate on their phone alongside their CDL scan. If you're ever uncertain at a scale or checkpoint, you want that document retrievable in seconds.
- If you operate a Freightliner, Ford, International, Kenworth, or Peterbilt, be aware that our data shows these vehicle makes appear most frequently in 391.45(b) citation records — not because of anything mechanical, but because they are common in fleets where this documentation gap has historically been missed. If you drive one of these units regularly, make the certificate check part of your standard pre-trip for that specific truck.
- Coordinate with your fleet safety manager. If your carrier maintains driver qualification files, confirm that your new certificate is on file immediately after each renewal. A mismatch between the physical certificate you carry and what's on file with your carrier or licensing agency can create separate documentation problems.
- Don't drive if you're unsure. If you cannot locate your current medical certificate before a trip and you are not certain it's valid, contact your dispatcher before moving. The cost of a delay is far lower than the citation and SMS impact of a 391.45(b) on your record.