What 393.75B-TFV means in plain language
This violation comes down to one measurement on one specific part of your truck: the tread depth on your steer axle tires. Federal rules require that those tires carry at least 4/32 of an inch of tread across the major grooves. If an inspector measures your steer tires and finds anything less than that threshold, you get cited under 393.75B-TFV.
The steer axle matters more than any other position on the vehicle because it's what you use to control direction. Worn tread on steer tires compromises wet-road grip, increases stopping distances, and raises the risk of hydroplaning. That's why the standard here is stricter than the 2/32-inch minimum that applies to tires on other axle positions.
The fix sounds simple — keep fresh tires up front — but the citation typically means an inspector caught something your pre-trip missed, or that tread wore down faster than expected between inspections. Either way, the paper now follows your CDL and your carrier's CSA record.
What our enforcement data actually shows
Across our 13 million+ inspection records, 393.75B-TFV has generated 7,764 all-time citations, placing it at #267 out of 3,036 FMCSR codes by volume. That's a meaningful enforcement presence — this isn't an obscure technicality inspectors rarely pursue.
The out-of-service picture, though, is genuinely good news for you. Our inspection records show that only 23 of those 7,764 citations resulted in an out-of-service order — a 0.3% OOS rate. The all-FMCSR average OOS rate across our database is 31.4%, so 393.75B-TFV sits dramatically below the norm. In practical terms: the overwhelming majority of drivers cited for this violation — 7,741 out of 7,764 — were allowed to continue operating after receiving the citation.
Recent volume is trending upward. In the last 12 months our database recorded 4,587 citations for this code, and 798 of those came in just the last 90 days. The monthly trend data shows enforcement was heaviest in mid-2025, peaking at 513 citations in August 2025, and has moderated somewhat into early 2026 — but remains active, with 341 citations in March 2026 alone.
The CSA severity weight is 7, which is not trivial. Even without an OOS event, each citation adds points to your carrier's Vehicle Maintenance BASIC score and to your driver record. Accumulating these over time moves the needle.
Who gets cited most
Looking at our inspection records for the last 180 days, California leads all states with 298 citations — and it's the only top-10 state showing any meaningful OOS rate at 1.7% (5 out-of-service events). That's still low in absolute terms, but it does stand apart from every other high-volume state in our data, including New York (137 citations, 0.0% OOS) and Pennsylvania (95 citations, 0.0% OOS). If you're running California routes regularly, be aware that inspectors there are slightly more likely to escalate to an OOS order than their counterparts elsewhere.
Missouri (84 citations), Maryland (62 citations), Georgia (53 citations), Wisconsin (52 citations), Virginia (49 citations), and Kansas (46 citations) round out the top ten, all with 0.0% OOS rates in the last 180 days.
On the carrier side, our data shows fleets such as DANIEL ERNESTO PENA COTA (USDOT 1647639) with 33 all-time citations and CNC LOGISTICS S DE RL DE CV (USDOT 2726203) with 32 all-time citations appearing at the top of our carrier frequency list for this code.
Freightliner units account for the single largest share of cited vehicles in our database at 1,235 citations, followed by Ford at 1,012 and International at 588. If you're driving one of these makes, your pre-trip tire check is especially worth doing carefully.
How severe is this compared to similar codes
Putting 393.75B-TFV in context alongside peer Vehicle Maintenance codes helps frame how serious this is relative to other things that can go wrong at a roadside inspection.
Consider 396.3(a)(1) — Inspection/repair/maintenance (general): our database shows 236,919 all-time citations for that code and a 45.3% OOS rate. That means nearly half of drivers cited under that general maintenance code get parked immediately. Your steer-tire tread citation at 0.3% OOS is a dramatically different enforcement outcome.
393.9(a) — Inoperable required lamps has 660,737 citations in our records — nearly 85 times the volume of 393.75B-TFV — with a 15.4% OOS rate. That code dwarfs steer-tire tread violations in both frequency and severity.
Closer to home, 396.17C-PI — No proof of periodic inspection shows 212,081 citations and a 0.0% OOS rate, much like 393.75B-TFV. Worth noting: in the last 90 days, our data shows 396.17C-PI appeared on 123 of the same inspections as 393.75B-TFV, suggesting drivers who lack current inspection paperwork are also more likely to be running worn steer tires.
How to avoid it
The co-occurring violation patterns in our 90-day data point directly to what's going wrong on these inspections. Here's what to do before you pull out of the yard:
- Measure steer tread depth at every pre-trip. A tire depth gauge costs a few dollars. The 4/32-inch mark is your hard floor on steers — if you're close, that tire needs to come off before your next run, not after.
- Check all other axle tires while you're at it. Our data shows that 393.75C-TAOTD-LT2/32 (insufficient tread on non-steer axles) appeared on 155 of the same inspections in the last 90 days. Worn steer tires and worn drive or trailer tires tend to travel together.
- Carry and verify your periodic inspection documentation. With 123 co-occurring appearances of 396.17C-PI (no proof of periodic inspection) in the last 90 days, missing paperwork is clearly a companion problem on these stops. Know where your annual inspection record is before you leave.
- Do a full lamp check. Inoperable required lamps (393.9A-LIL) showed up on 93 shared inspections in our 90-day window. A burned marker light or headlamp is often what triggers a closer look that leads to a tire measurement.
- Confirm your fire extinguisher and warning devices are present and accessible. Our data shows 70 shared inspections included a missing or improperly rated fire extinguisher (393.95A1) and 62 included a warning device violation (393.95F). These are quick pre-trip checks that remove easy citation targets.
- Look for tire inflation issues at the same time. Code 393.75A3-TAOL (tires leaking or underinflated below 50% of max pressure) appeared on 66 shared inspections in the last 90 days. An underinflated tire also wears faster and unevenly, accelerating the tread-depth problem.
- Freightliner, Ford, and International drivers: our records show those three makes account for 2,835 citations combined under this code. Nothing inherent to the platform causes this — but if you're in one of those cabs, your tire maintenance history is worth a harder look.