What 393.75A means in plain language
FMCSR 393.75A covers the basic condition of the tires and tubes on your commercial motor vehicle. The regulation requires that every tire mounted on your rig meets minimum acceptable standards — not just for tread depth, but for the overall physical condition of the tire itself. That means cracks, bulges, exposed cords, improper repairs, or any other defect that compromises the tire's integrity can put you in violation.
The rule applies broadly. It doesn't matter whether the defective tire is on a steer axle, a drive axle, or a trailer axle — if it's mounted on the vehicle and rolling down the highway, it has to be in serviceable condition. Inspectors are trained to spot problems you might miss during a rushed pre-trip: sidewall damage that's been overlooked for weeks, a bead that isn't seating correctly, or a tube-type tire with an improper valve stem.
The distinction between 393.75A and related tire codes matters. This is the general-defects provision — it catches the broad range of tire problems that don't fit a more specific subcategory. Think of it as the catch-all that an inspector reaches for when the tire clearly shouldn't be on the road but the problem is a physical defect rather than a straightforward tread measurement.
What our enforcement data actually shows
The numbers behind 393.75A are among the most striking in the Vehicle Maintenance category. Across our inspection records, this code carries a 90.0% out-of-service rate — meaning nine out of every ten citations resulted in the driver being placed out of service on the spot. To put that in context, the all-FMCSR average OOS rate across all codes is 31.4%. This code runs nearly three times that average.
Although 393.75A is listed as OOS-eligible: no at the regulatory level, our database of 13 million-plus inspections tells a different story in practice: 11,431 of the 12,699 all-time citations resulted in an OOS order, with only 1,268 citations that did not. Inspectors are consistently treating tire general defects as an immediate safety threat.
Volume is significant and accelerating. Over the last 12 months our records show 8,378 citations — meaning roughly 66% of all all-time citations for this code have occurred in just the past year. The last 90 days alone account for 1,836 citations. Nationally, this code ranks #193 out of 3,036 FMCSR codes by citation count, placing it firmly in the top 7% of all codes for enforcement frequency.
Monthly data shows persistent enforcement activity. October 2025 was the heaviest single month in the trailing 12, with 845 citations and 769 of those resulting in OOS orders. March 2026 came close behind at 833 citations and 764 OOS placements. There is no low season — even the quieter months like November 2025 still produced 615 citations and 549 OOS orders.
Who gets cited most
Looking at the last 180 days, three states dominate the citation map. Texas leads with 1,682 citations, of which 1,494 resulted in OOS placement — an 88.8% OOS rate. North Carolina is second with 1,420 citations and a notably higher OOS rate of 98.2%, meaning that in NC, virtually every 393.75A citation ends with the vehicle parked. Illinois is third at 462 citations and a 78.8% OOS rate. The spread between Illinois and North Carolina — nearly 20 percentage points — is material and worth noting if your lanes run through those states.
Among carriers in our all-time data, fleets such as Swift Transportation Co of Arizona LLC (USDOT 54283) with 68 citations and Federal Express Corporation (USDOT 86876) with 59 citations appear at the top of the volume list. These are large national fleets with enormous equipment counts, and their presence here reflects scale as much as anything else — but the numbers do illustrate that no carrier size is exempt from 393.75A exposure.
How severe is this compared to similar codes
Within the Vehicle Maintenance category, 393.75A's 90.0% OOS rate stands apart. Consider a few peer codes for comparison. FMCSR 393.9(a), covering inoperable required lamps, has accumulated 660,737 citations in our database — more than 52 times the all-time volume of 393.75A — but carries only a 15.4% OOS rate. Inspectors are far more likely to write a lamp violation as a warning than to park the truck. FMCSR 396.3(a)(1), the general inspection, repair, and maintenance provision, has 236,919 citations and a 45.3% OOS rate — well above average, but still half of what 393.75A produces. FMCSR 393.78, covering defective windshield condition, sits at 157,894 citations with a 0.3% OOS rate — nearly every windshield citation is written without an OOS order. The pattern is clear: when it comes to tires, inspectors pull the trigger on OOS placement at a rate that has almost no parallel in this category. If you're cited under 393.75A, you are very likely going home without your load.
How to avoid it
The co-occurring violation data in our records gives a clear picture of what inspections that produce a 393.75A citation look like — and what you can address before you ever reach a weigh station.
- Walk every axle during your pre-trip. This sounds obvious, but our data shows 393.75A shares inspections with 393.75C (insufficient tread depth on other axles) in 93 cases in the last 90 days alone. Catching a degraded drive or trailer tire before departure is the same inspection motion that catches the defect an inspector will find.
- Check lamps and signals at the same time. In the last 90 days, 393.9 (inoperable required lamp) co-occurred with 393.75A in 293 shared inspections, and 393.9TS (inoperative turn signal) in 165. An inspector who stops you for a lamp is going to walk around the whole vehicle.
- Inspect your windshield. FMCSR 393.78 co-occurred in 149 shared inspections. Cracked or obstructed glass is a visible trigger that invites a thorough inspection of everything else — including your tires.
- Carry and verify your brake hardware. Slack adjuster issues under 393.47E appeared in 100 shared inspections. A brake-system walk-around that checks slack adjusters should be paired with a close look at the tires on those same axles.
- Confirm your periodic inspection documentation. FMCSR 396.17C (no proof of periodic inspection) co-occurred in 116 inspections. Having current PI paperwork in the cab tells an inspector your equipment is on a maintenance schedule — its absence invites deeper scrutiny.
- Know your vehicle make's exposure. FRHT (Freightliner) units account for 4,190 of all-time citations under this code — the highest of any make in our database — followed by KW (Kenworth) at 1,627 and PTRB (Peterbilt) at 1,318. If you're operating any of these makes, tire condition is a known enforcement focus for your platform.
- Look at the sidewalls, not just the tread. 393.75A is a general-defects code. Tread depth gets checked, but so do bulges, cuts, exposed cords, and improper repairs. Run your hand along the sidewall during pre-trip and look at the bead area where the tire meets the wheel.