What 393.78(a) means in plain language
This regulation targets one specific problem: a windshield in a condition that interferes with the driver's ability to see the road clearly. That could mean a large crack running through your line of sight, a starred impact point directly in front of the driver, significant discoloration, or any other damage that reduces visibility in a meaningful way.
The rule is not about cosmetic imperfections. A hairline crack at the edge of the glass that doesn't affect your sightlines is a different situation than a spiderweb fracture centered on the driver's side. Inspectors are looking at whether the damage materially compromises what you can see ahead of and around the vehicle.
In practical terms, if a roadside inspector can look at your windshield and argue that a reasonable driver's view of traffic, pedestrians, or road conditions is obstructed by the glass itself, you can be cited under 393.78(a). The fix is straightforward in theory — keep the glass in serviceable condition — but citations still accumulate because pre-trip inspections don't always treat the windshield with the same rigor as tires or brakes.
What our enforcement data actually shows
Across our database of 13 million+ inspections, 393.78(a) has generated 13,852 all-time citations. That volume puts it at #180 out of 3,036 FMCSR codes by citation count — solidly in the enforcement mainstream, not a rarely-enforced technicality.
One number stands out immediately: the out-of-service rate for this code is 0.0%. In all 13,852 recorded citations, not a single driver was placed out of service. Compare that to the all-FMCSR average OOS rate of 31.4%, and it becomes clear that inspectors are writing this violation but not pulling trucks off the road for it. The code is marked OOS-ineligible, which explains that outcome — but it also means enforcement is purely a citation-and-CSA-points event rather than an immediate operational shutdown.
In the last 12 months our inspection records show 0 citations, and in the last 90 days the count is also 0. That recent drop-off in activity is worth noting: enforcement attention on this specific sub-code has apparently quieted in the near term, though the 13,852 all-time total confirms it was actively cited for an extended period.
Who gets cited most
The STATISTICS block for this code does not include a state-by-state breakdown, so no state-level claims can be made here. What the data does show is which fleets and operators appear most frequently in the citation records.
Our data shows fleets such as OCTAVIO ANDRADE CORELLA (USDOT 558440) with 34 citations, BELTRAN BROTHERS LLC (USDOT 1122039) with 28 citations, and RICARDO ANDRES PENA COTA (USDOT 591357) with 28 citations appearing at the top of the all-time list. The presence of multiple smaller operators alongside larger fleets like FEDERAL EXPRESS CORPORATION (USDOT 86876) with 21 citations suggests this violation is not limited to any single carrier type or operation size — it shows up across the board.
On the equipment side, our inspection records show Freightliner vehicles leading with 3,830 citations under this code, followed by Kenworth at 2,174 and Peterbilt at 2,058. These three makes together account for a large share of the total, which tracks with their dominant share of the Class 8 fleet overall rather than indicating a specific structural defect with those manufacturers' glass.
How severe is this compared to similar codes
Within the Vehicle Maintenance category, 393.78(a) sits at a CSA severity weight of 4. Looking at peer codes in the same category puts that in context.
393.9(a) — Inoperable required lamps has 660,737 citations in our database and carries a 15.4% OOS rate. That's nearly 48 times the citation volume of 393.78(a), and inspectors are placing drivers out of service for it at a meaningful rate. Lighting defects clearly attract far more enforcement attention and carry real OOS risk.
396.3(a)(1) — Inspection, repair, and maintenance (general) shows 236,919 citations and a 45.3% OOS rate — well above the 31.4% all-FMCSR average. When inspectors write that general maintenance catch-all, nearly half of those inspections end with the truck parked. That's a fundamentally different risk profile than 393.78(a)'s 0.0% OOS rate.
For the closest direct comparison, the broader 393.78 — Windshield condition defective code (the parent code without the sub-part designation) shows 157,894 citations at a 0.3% OOS rate. That parent code has more than eleven times the volume of the 393.78(a) sub-code, which suggests inspectors more often cite the general windshield condition violation rather than the specific sub-part. Either way, the OOS exposure across the windshield family remains near zero.
The takeaway: a 393.78(a) citation won't park your truck, but it will add CSA points at a severity weight of 4, and repeated hits will move the needle on your Vehicle Maintenance BASIC score.
How to avoid it
Because every one of the 13,852 citations resulted in a driver continuing down the road (0.0% OOS), this is entirely a pre-trip and maintenance discipline problem. Here's what to do:
- Inspect the windshield as a dedicated pre-trip step. Stand outside the cab and visually scan the full glass surface — driver's side, passenger's side, and center — before every dispatch. Don't do this from the seat; the angle hides cracks that are obvious from outside.
- Know the difference between cosmetic and functional damage. An edge chip outside your direct sightline is different from a crack that bisects your forward view. If you have to move your head to see around damage, it's functional impairment and needs to be reported.
- Write it up on your DVIR immediately. If you find a crack or starred impact during pre-trip that falls in your sightline, document it on the Driver Vehicle Inspection Report before you leave the yard. Driving with known impairment and then getting cited is a harder position to be in than having a repair order open.
- Pay attention to Freightliner, Kenworth, and Peterbilt cabs specifically. Our data shows these makes account for the highest citation counts — 3,830, 2,174, and 2,058 respectively. If you're operating one of these trucks, make the windshield check a non-negotiable item rather than a quick glance.
- Report chips before they crack. A small impact point from road debris can travel across the glass in cold weather or under vibration. A $30 chip repair at the yard is cheaper than a CSA-weighted citation on your record and a windshield replacement later.
- Don't assume a dirty windshield shields you from the citation. Clean the glass as part of pre-trip. Inspectors evaluating condition can ask you to clean it, and what's underneath the grime may be what gets written up.