What 393.65B means in plain language
FMCSR 393.65B prohibits operating a commercial motor vehicle when any tire is flat or has an audible air leak. This is a straightforward safety rule: your tires must be properly inflated and free of active leaks before you drive.
The regulation applies to all tires on your vehicle — steer tires, drive tires, and trailer tires. A tire with a slow leak that you can hear (sometimes described as a hissing sound) counts as a violation, even if the tire isn't completely flat yet. Inspectors check this during roadside inspections by visual inspection and sometimes by listening for air escaping.
This is not about tread depth or wear patterns. It's specifically about structural integrity and inflation pressure. If your tire is losing air noticeably, it's out of compliance.
What our enforcement data actually shows
Across our 13 million+ inspection records, 393.65B is cited rarely and never results in an out-of-service order. Our data shows 23 all-time citations for this code, with 17 citations in the last 12 months and 8 in the last 90 days. The out-of-service rate is 0.0% — none of the 23 citations resulted in a vehicle being placed out of service.
For context, the all-FMCSR average out-of-service rate is 31.4%. That means 393.65B citations almost never escalate to immediate roadside removal from service. However, the citation still carries a CSA severity weight of 8, which means it counts against your safety record and can affect your company's FMCSA scores.
Ranked #1881 of 3,036 FMCSR codes by citation volume, this violation is comparatively rare, but when it does occur, it signals a basic pre-trip inspection failure.
Who gets cited most
Our inspection records show Texas dominates the enforcement landscape for this code, with 16 citations over the last 180 days and a 0.0% out-of-service rate. This geographic concentration reflects both Texas traffic volume and the state's roadside inspection activity.
Among carriers in our records, several small and independent operators have been cited multiple times. Our data shows fleets and owner-operators such as those managed under USDOT 4149865, USDOT 4182303, and USDOT 1064757 have each received 2 citations for this violation. This does not imply negligence — it reflects that tire maintenance issues can emerge across any operation if pre-trip procedures are incomplete.
How severe is this compared to similar codes
Within the Vehicle Maintenance category, tire and lighting violations vary widely in enforcement volume and consequence. For comparison:
- 393.9 (Inoperable Required Lamp): 180,097 all-time citations with a 6.9% out-of-service rate. Lighting violations are far more common and more likely to trigger roadside removal.
- 393.78 (Windshield Condition Defective): 157,894 citations with a 0.3% out-of-service rate. Like 393.65B, windshield violations rarely lead to out-of-service action, but occur much more frequently.
- 396.3(a)(1) (Inspection/Repair/Maintenance — General): 236,919 citations with a 45.3% out-of-service rate. Broader maintenance violations carry significantly higher enforcement severity and roadside consequences.
393.65B is citation-light and almost never results in out-of-service action, but the violation points to a gap in your pre-trip inspection routine.
How to avoid it
Flat and leaking tire citations are entirely preventable with a disciplined pre-trip inspection. Our co-occurring violation data reveals patterns that point to the root causes:
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Walk around your entire vehicle before departure. Check all tires visually for obvious flattening or damage. Listen for hissing or air leaks, especially around the valve stem and sidewall. Our data shows that 396.3A1 (Inspection, repair and maintenance of parts and accessories) commonly appears in the same inspection, indicating that inspectors catch multiple maintenance gaps when one pre-trip step is skipped.
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Invest in a tire pressure gauge and use it. Don't rely on visual inspection alone. Know the correct PSI for your vehicle (check the driver door jamb or vehicle manual), and verify at least once per week during layovers. Pressure changes with temperature and time.
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Check for wear and sidewall damage during pre-trip. Look for cracks, bulges, or punctures. Our enforcement records include citations on Kenworth (7 citations), Volvo (4 citations), and International (2 citations) units, indicating that the violation spans all major makes — the common factor is incomplete tire inspection, not vehicle brand.
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Don't defer tire maintenance. If you notice a slow leak or suspect a tire is losing pressure, get it repaired before your next dispatch. Our data shows 393.65F (another tire-related code) and 393.45B2UV (brake tubing/hoses inadequate) co-occurring in the same inspections, suggesting that deferred maintenance cascades into multiple violations.
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Document your pre-trip checks. Many carriers require drivers to initial a vehicle inspection report before departure. This creates accountability and evidence that you performed the check — critical if you're audited.
The fact that this citation has never resulted in out-of-service action in our records doesn't mean you should ignore it. It means inspectors see it as a checkpoint violation, a sign that you skipped a step. Repeat citations or multiple maintenance violations in a single inspection can damage your carrier's CSA scores and limit your opportunities with shippers and brokers.