FMCSR 390.21(a) Vehicle Marking Violations: Driver Q&A

No. Across all 25,872 recorded citations for 390.21(a) in our inspection database, only 3 vehicles were ever placed out of service—producing an effective OOS rate of 0.0%. For context, the all-FMCSR average OOS rate is 31.4%, so this violation sits far below the threshold that typically triggers a shutdown. You will almost certainly be allowed to continue operating after receiving this citation, but the violation still writes to your inspection record and feeds your CSA score, so it cannot be ignored.

390.21(a) carries a severity weight of 3 in the CSA scoring system. That base score is then multiplied by a time-weight factor: violations from the most recent 6 months count at full value, those from 6–12 months back are reduced, and anything older than 2 years drops off entirely. Because this is an Admin/General BASIC violation, it affects the Vehicle Maintenance BASIC category for the carrier. The severity weight of 3 is on the lower end of the 1–10 scale, but with 9,685 citations recorded just in the last 12 months, inspectors are clearly writing it consistently.

Act on marking compliance before your next dispatch, and audit the related violations that inspectors find alongside this one. Here's what the data suggests:

1. Fix the marking immediately. Ensure your cab door displays the carrier's legal name and USDOT number in the required size and contrast.
2. Check your lamps. In the last 90 days, 793 inspections that included a 390.21(a) citation also flagged 393.9 (inoperable required lamp).
3. Verify your periodic inspection paperwork. 699 of those same inspections also generated a 396.17C citation for missing proof of periodic inspection.
4. Confirm your medical certificate is on file. 283 co-cited inspections also hit 391.41APC.
5. Check your fire extinguisher. 452 inspections added a 393.95A citation at the same stop.

It's mid-range in volume but identical in OOS risk compared to its peers. Among related marking codes in the same category, 390.21TB2-DOT has 74,663 citations and 390.21T(b) has 61,097—both dwarfing 390.21(a)'s 25,872. However, every peer code in this category also sits at a 0.0% OOS rate, and the all-FMCSR average is 31.4%, so the entire vehicle-marking group is low-risk for shutdowns. What separates 390.21(a) from peers isn't severity—it's enforcement frequency. At rank #108 out of 3,036 FMCSR codes by citation volume, inspectors are writing it regularly enough that it will accumulate on a fleet's record if left unmanaged.

Yes, and documentation violations like this one are among the more contestable findings. Because 390.21(a) is about whether your vehicle displayed the correct legal name and USDOT number at the time of inspection—a factual, observable condition—you can challenge the record through FMCSA's DataQs system (the Request for Data Review, or RDR process) if you have evidence the markings were actually present and compliant. Useful evidence includes dated photographs of the cab door, vehicle registration records, or inspection reports from before or after the stop. Submit your RDR at dataqs.fmcsa.dot.gov and be specific about what the officer recorded versus what the vehicle actually showed.

Texas is by far the dominant enforcement state for this violation. Our inspection records for the last 180 days show:

• Texas: 4,470 citations, 0 OOS placements
• North Carolina: 151 citations, 0 OOS placements
• New Mexico: 18 citations, 0 OOS placements

Texas accounts for the overwhelming share of recent enforcement activity, which tracks with the high concentration of cross-border commercial traffic on Texas corridors. Several of the top-cited carriers in our all-time data—including LUCA AUTOTRANSPORTES SA DE CV (47 citations) and PETROLIFICOS DE MONTERREY SA DE CV (24 citations)—operate international routes that pass through Texas ports of entry.

Very urgent from a CSA accumulation standpoint, even though shutdown risk is essentially zero. Our records show 2,096 citations issued in just the last 90 days, and the monthly trend over the past year has been consistently high—ranging from 770 to 968 citations per month between May 2025 and February 2026. That volume tells you inspectors are not overlooking this. Every citation adds a severity-3 hit to your CSA record. A fleet running multiple trucks with unmarked or incorrectly marked vehicles can accumulate enough points across a quarter to push its Admin BASIC percentile into alert territory. Marking a truck correctly takes minutes; the CSA consequences of not doing it compound with each inspection.

It affects both, but in different ways. Under FMCSA's CSA methodology, vehicle marking violations like 390.21(a) are attributed to the carrier's safety record because the obligation to mark the vehicle rests with the motor carrier operating it—not the individual driver. The citation will appear on the carrier's BASIC data. However, the inspection record is tied to the vehicle and the driver present at the stop, meaning a driver who repeatedly operates unmarked equipment can see patterns reflected in inspection history that follow them between employers. Our all-time data shows carriers like REPUBLIC WASTE SERVICES OF TEXAS LTD accumulating 24 citations and AGGREGATE HAULERS I L P accumulating 22 citations, illustrating how fleet-level failures stack up on the carrier side.