What 393.84 means in plain language
FMCSR 393.84 requires that the floor of your commercial motor vehicle be substantially constructed, free of unnecessary holes, and properly maintained. In other words, the floor under your cab, sleeper, or cargo area cannot have significant damage, rot, corrosion, or holes that compromise the structural integrity of the vehicle or create a safety hazard.
Inspectors look for rust-through, missing floorboards, rot in wooden components, or holes large enough that debris, water, or contaminants could enter or escape from the vehicle. A few surface dents or minor wear don't trigger a citation—the floor has to be substantially compromised. The regulation exists to ensure the vehicle remains safe to operate and doesn't shed cargo or parts onto the roadway.
What our enforcement data actually shows
Across our 13 million roadside inspection records, 393.84 has generated 901 citations all-time, with 188 citations in the last 12 months and 43 in the last 90 days. This ranks 393.84 at #742 of 3,036 FMCSR codes by citation volume—it's not a high-frequency violation.
Here's the critical fact: only 2.1% of 393.84 citations result in an out-of-service order. That means 19 out of 901 citations placed the truck OOS, while 882 were cited as a defect to be corrected. For comparison, the all-FMCSR average OOS rate is 31.4%, so defective floors are cited far more leniently than many other violations. Inspectors view this as a maintenance issue with time to correct, not an immediate safety emergency.
The 12-month trend shows 188 citations spread fairly evenly across months, with a peak in September 2025 (22 citations) and lower activity in April 2026 (1 citation). The out-of-service events have been rare and sporadic—only 3 OOS orders across the last 12 months, all in June, August, and October.
Who gets cited most
Our enforcement records show Texas leads by a wide margin: 81 citations in the last 180 days with a 0.0% OOS rate. New Mexico follows with 3 citations (0.0% OOS), and Illinois with 1 citation (0.0% OOS). Texas accounts for the overwhelming majority of 393.84 enforcement activity in the dataset.
Among carriers with the highest citation counts all-time, our data shows fleets such as Friendly Harbor Services Inc (USDOT 1739188) with 8 citations and Empowering People Workshop Inc (USDOT 2424128) with 7 citations. These counts are low in absolute terms and do not suggest systematic negligence; rather, they reflect the rarity of the violation and the normal operational variance across carriers.
How severe is this compared to similar codes
393.84 sits among vehicle maintenance and structural defect codes. For perspective:
- 393.9 (Inoperable Required Lamp) has 660,737 citations with a 15.4% OOS rate. Lighting violations are 733 times more frequent than defective floors and are out-of-serviced at a much higher rate.
- 396.3(a)(1) (Inspection/Repair/Maintenance—General) has 236,919 citations with a 45.3% OOS rate. This catch-all maintenance code is cited far more often and pulls vehicles OOS at rates well above the all-FMCSR average.
- 393.78 (Windshield Condition Defective) has 157,894 citations with only a 0.3% OOS rate. Like 393.84, windshield defects are treated as correctable maintenance items, though they are cited roughly 175 times more frequently.
The takeaway: defective floors are a rare citation and treated lightly by enforcement because they rarely pose an acute safety risk on the road.
How to avoid it
Floor defects develop over time through normal wear, exposure to water and salt, and impact damage. Here are concrete steps to prevent a citation:
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Conduct a monthly under-vehicle walk-around inspection. Get down and look at the floor from outside the cab. Check for holes, rust, soft spots, or separation of floor panels. Pay special attention to the area under the driver and passenger feet and around the sleeper cab, where moisture accumulates.
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Address rust and corrosion early. If you spot surface rust or small areas of discoloration, clean and treat them with rust inhibitor. Don't wait for holes to form. Small maintenance now prevents costly repairs later.
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Inspect after long periods of wet weather or exposure to salt. Winter driving and coastal routes accelerate floor degradation. Schedule extra inspections if you regularly operate in harsh environments.
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Check floor seals and weather stripping. Water intrusion is a primary cause of floor rot. Ensure door seals are intact and drainage holes under the cab are not clogged. Water pooling under the vehicle accelerates structural failure.
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Document repairs and maintenance. Keep records of any floor repairs, welding, or replacement work. This shows your commitment to compliance if questioned and helps your maintenance team track problem areas on specific units.
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Be especially attentive if your vehicle is a Freightliner, Ford, or Kenworth. Our records show Freightliners (101 citations), Fords (78), and Kenworths (53) account for the highest citation counts. This likely reflects fleet size and exposure rather than a design defect, but it means inspectors may scrutinize these makes more carefully.
If you've already been cited for 393.84, the inspector is telling you the floor needs repair or replacement before the next inspection. You do not face an out-of-service order in most cases, so you can continue to operate while you schedule the work. Contact your fleet maintenance or owner-operator shop and get it on the schedule. This is a correctable defect, not a violation that will haunt your record if you address it promptly.