Can a Commercial Driver Drive While Ill or Fatigued under FMCSA Rules?

No. Under 49 CFR 392.3, a driver may not operate a commercial motor vehicle, and a motor carrier may not require or permit it, while the driver's ability or alertness is so impaired, or so likely to become impaired, through fatigue, illness or any other cause that it is unsafe to begin or continue driving. A narrow grave-emergency exception applies.

The rule. 49 CFR 392.3 applies to both the driver and the motor carrier. The test is whether the driver's ability or alertness is so impaired, or so likely to become impaired, through fatigue, illness or any other cause, that it would be unsafe to begin or continue operating the CMV.

Grave emergency exception. If complying would increase the hazard to vehicle occupants or other highway users, the driver may continue to the nearest place where that hazard is removed.

How it fits with hours of service. The hours-of-service limits in 49 CFR Part 395 set maximum driving and on-duty time, but staying within them does not satisfy 392.3 if the driver is actually too fatigued or ill to drive safely. The Learn Laws® FAQ on hours-of-service limits for property-carrying drivers covers the numeric limits.

Related prohibitions.

• Drugs and other substances (49 CFR 392.4). No driver may be on duty and possess, be under the influence of, or use Schedule I substances, amphetamines, narcotics, or any other substance to a degree that makes the driver incapable of safe operation. Except for Schedule I substances, which have no exception, 392.4(c) excepts substances administered by or under the instructions of a licensed medical practitioner who has advised that the substance will not affect safe driving.
• Alcohol (49 CFR 392.5). No alcohol use within 4 hours before going on duty or operating a CMV, and no measured alcohol concentration while on duty. A violation results in a 24-hour out-of-service order.

Learn Laws® is a training company, not a law firm. This FAQ is general information, not legal advice.