What 392.3 means in plain language
FMCSR 392.3 prohibits operating a commercial motor vehicle while ill or fatigued. In practical terms, this means a DOT inspector can place you out of service if they observe signs that you are not physically or mentally fit to operate a truck safely—whether due to illness, fatigue, or any condition that impairs your ability to drive.
The regulation exists because driver incapacity is a direct safety threat. An inspector may cite you based on observable behavior: erratic steering, difficulty maintaining lane position, slurred speech, drowsiness, or verbal admission that you are unwell. This is not a paperwork violation; it is a judgment call about whether you can safely control your vehicle right now.
Unlike citations for equipment defects or record-keeping errors, a 392.3 citation typically results in immediate removal from service. You will not be allowed to continue driving until you are deemed fit to operate.
What our enforcement data actually shows
Across 13 million roadside inspections, 392.3 has generated 1,312 citations all-time, with 172 citations in the last 12 months and 32 in the last 90 days. This places 392.3 at rank #647 of 3,036 FMCSR codes by citation volume—a relatively rare citation.
However, the severity is stark: our inspection records show that 98.0% of 392.3 citations result in an out-of-service order. That means 1,286 of 1,312 citations led to removal from duty. For context, the all-FMCSR average out-of-service rate is 31.4%. A 392.3 citation is nearly three times more likely to pull you off the road than the typical FMCSR violation.
This high OOS rate reflects the regulatory intent: if an inspector believes you are unfit to drive, they will not allow you to continue until the concern is resolved. The data shows inspectors are consistent in this enforcement posture across all citations recorded.
Who gets cited most
Over the last 180 days, Illinois leads with 47 citations and a 95.7% out-of-service rate. Iowa follows with 13 citations at a 100.0% OOS rate, and Texas reports 9 citations also at 100.0%. The variation in OOS rates is small—ranging from 95.7% to 100%—indicating that enforcement severity for this code is uniform regardless of state.
Our data shows major carriers such as Western Express Inc (USDOT 511412) with 10 all-time citations, and XPO Logistics Freight Inc (USDOT 241829) with 7 citations. These numbers reflect the scale of their fleets and operational hours rather than any particular safety program weakness; the data does not identify systemic patterns tied to carrier negligence.
How severe is this compared to similar codes
392.3 sits within a cluster of fatigue and incapacity codes. The most common peer code is 392.2, which carries the same label and has generated 1,208,164 citations all-time—nearly 1,000 times the volume of 392.3. However, 392.2 has a 0.8% out-of-service rate. This large gap suggests that 392.2 citations are issued more routinely (perhaps for minor or borderline fatigue indicators), while 392.3 citations are reserved for severe or unambiguous cases that warrant immediate removal from service.
Other related codes like 392.2-SLLEQP show a 2.4% OOS rate and 72,352 citations all-time, and 392.2-SLLEWA1 shows a 1.0% OOS rate across 69,565 citations. These variants underscore that the broader fatigue-and-incapacity category is frequently enforced but rarely results in an out-of-service order. When 392.3 is cited, it signals an inspector's high confidence that you are unsafe to drive.
How to avoid it
The following actions reduce your risk of a 392.3 citation:
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Plan rest before fatigue sets in. Do not wait until you feel drowsy. Take a break at the first sign of reduced alertness—heavy eyelids, difficulty focusing, or slower reaction time. Inspectors are trained to spot these signs; by resting early, you avoid the situation that triggers a citation.
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Manage illness proactively. If you are coughing, feverish, or experiencing pain that affects concentration, inform your dispatcher and take a day off. Operating while symptomatic puts you at risk of a citation and endangers other road users. Many carriers have explicit policies requiring drivers to self-report illness.
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Maintain a sleep schedule. Our inspection records show that fatigue citations tend to cluster around consistent patterns; drivers working irregular or night-heavy schedules are more vulnerable. If you can negotiate consistent hours, your alertness will improve and your citation risk will drop.
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Conduct a pre-trip clarity check. Before leaving the truck stop or before a long stretch, spend 30 seconds checking your own state: Are you thinking clearly? Is your vision sharp? Can you control the wheel smoothly? If the answer to any is no, do not drive.
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Know your co-occurring risks. Our data shows that 392.3 citations frequently occur alongside false records of duty status (395.8E, 7 shared inspections) and speeding violations (392.2-SLLS1, 4 shared inspections). This pattern suggests that fatigued or unwell drivers often cut corners on logbook accuracy and speed control. By maintaining honest logs and respecting speed limits, you reduce the likelihood that an inspector will scrutinize your behavior closely enough to notice incapacity.
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Inspect common vehicle systems before fatigue can cause problems. The most-cited vehicle makes in 392.3 violations include Freightliners (213 citations), Volvo trucks (78), and Kenworth models (59). While the vehicle make itself is not a causal factor, these high-volume fleets may operate longer routes and higher mileage, increasing fatigue exposure. Pre-trip inspections of brakes, steering, and lighting help you catch mechanical problems that might otherwise cause you to over-concentrate and become more fatigued.
In short: listen to your body, communicate with your dispatcher, and rest before you reach the point of obvious impairment. A 392.3 citation almost certainly means going out of service, and the economic and schedule impact is severe.