What 392.3-I means in plain language
FMCSR 392.3-I prohibits you from operating a commercial motor vehicle when you are impaired by illness or other physical or mental cause. This is distinct from fatigue or other specific conditions—it's a catch-all rule that covers any medical or health condition that reduces your ability to safely control the truck.
"Impaired" doesn't necessarily mean you're incapacitated. It means your condition materially compromises your judgment, coordination, alertness, or physical capability to operate the vehicle. Examples include acute illness (fever, severe headache, dizziness, nausea), untreated medical conditions (uncontrolled diabetes, seizure disorders, severe sleep apnea), or medication side effects that impair cognition or motor control.
Inspectors cite this code when they observe signs that you appear unfit to drive—slurred speech, tremors, confusion, erratic steering, or when you disclose a condition you should have reported before getting behind the wheel. The regulation puts the responsibility on you to recognize when you're not safe and to stop driving.
What our enforcement data actually shows
Across our 13 million+ inspection records, 392.3-I ranks #1037 of 3,036 FMCSR codes by citation volume. While not the most-cited code, it carries exceptional enforcement consequence: our database shows a 97.7% out-of-service rate for this violation. This is far above the all-FMCSR average of 31.4%, meaning drivers cited for 392.3-I are almost certainly taken out of service on the spot.
Over the last 12 months, we recorded 206 citations for 392.3-I. In the last 90 days, that pace continued with 40 citations, averaging roughly 13–14 per month. Monthly data from our records show activity ranging from 6 citations in April 2025 to 21 citations in September and November 2025, with sustained volume through early 2026.
Of the 347 all-time citations in our database for this code, 339 resulted in out-of-service placement. Only 8 were not removed from service, suggesting inspectors treat impairment very seriously regardless of the specific illness.
Who gets cited most
Our data shows Georgia leads by citation count over the last 180 days with 14 citations, all resulting in out-of-service placements (100%). Massachusetts follows with 7 citations and a 100% OOS rate. Arizona recorded 7 citations with 6 out-of-service placements, a rate of 85.7%—the only top state with variation, likely reflecting differences in inspectors' judgment calls on symptom severity.
Inland states including Indiana, Pennsylvania, Colorado, Ohio, Nebraska, Nevada, and Washington each recorded 4–6 citations, all at 100% OOS rates. The consistent near-universal out-of-service placement across geographies underscores how strictly this violation is enforced nationwide.
Our all-time data identifies fleets such as A One American Trucking Inc and XPO Logistics Freight Inc with 3 citations each in our records, and J B Hunt Transport Inc also at 3 citations. These figures reflect the carrier universe and do not imply fleet safety performance relative to peers—individual driver decisions and medical circumstances drive most citations.
How severe is this compared to similar codes
Code 392.2—Operating a CMV while ill or fatigued—is the closest peer. Our records show 1,208,164 citations for 392.2 with a 0.8% out-of-service rate. The contrast is stark: 392.3-I has 347 all-time citations but a 97.7% OOS rate, while 392.2 has orders of magnitude more citations but only 0.8% result in out-of-service placement.
Other related codes like 392.2-SLLSR (Operating a CMV while ill or fatigued, specific subcategory) show 191,232 citations with a 0.1% OOS rate, and 392.2-SLL reflects 84,501 citations at 0.2% OOS. The pattern is clear: 392.3-I is cited far less often but enforcement is dramatically stricter. Inspectors reserve this code for cases of obvious, material impairment where immediate removal from service is the only safe option.
How to avoid it
Before you drive:
- Honestly assess your health each morning. If you have a fever, significant pain, dizziness, or medication side effects that affect alertness or coordination, do not operate. Call your dispatcher and delay the load.
- Review any new or recently adjusted medications with a pharmacist or doctor before your next trip. Ask specifically whether they cause drowsiness, dizziness, or reduced motor control. If yes, do not drive until the dose stabilizes or you can take it off-duty.
- If you have a chronic condition (diabetes, sleep apnea, seizure history, heart condition), confirm it is being actively managed by a healthcare provider and that your symptoms are controlled. Document this.
During your trip:
- Monitor yourself regularly at stops. If you develop unexpected dizziness, tremors, confusion, or feeling faint, pull over immediately and rest, hydrate, or call for relief.
- Our data shows 392.3-I commonly co-occurs with 392.2-SLLML (Operating a CMV while ill or fatigued) in 12 shared inspections over the last 90 days. This tells us impairment from illness often compounds fatigue. Do not let tiredness mask or worsen an underlying illness—they multiply each other.
- If an inspector asks how you feel or whether you're on medication, answer truthfully. Concealing a condition that's causing visible impairment will only make citation and out-of-service placement more certain.
After this citation:
- Expect to be out of service immediately. This is not a warning.
- Before you return to duty, obtain documentation from a healthcare provider confirming you are medically fit to operate a CMV. This protects both you and your carrier from future citations on the same issue.
- If the condition is chronic, work with occupational health or your primary care doctor to create a management plan so you can recognize early warning signs and avoid situations where you're impaired.