The FMCSR requires that CMV drivers stay alert at all times while driving. In the world we live in today, there are plenty of distractions that can get in the way of being 100% alert. Therefore, the regulations outline certain substances and distractions that can impair a driver’s ability to drive safely. Some examples of these include:

  • illness or fatigue

  • drug use or possession

  • alcohol use or possession

  • texting or using a hand-held cell phone while driving.

Drivers are prohibited from driving and motor carriers shall not require or permit a driver to operate a CMV while the driver’s ability or alertness is so impaired, through fatigue, illness, or any other cause, as to make it unsafe for the driver to operate the vehicle. The exception to this rule is when there is a grave emergency and continuing to drive is less hazardous to human life than not driving.

Additionally, no driver shall be on duty and posses, be under the influence of, or us any of the following drugs or substances: schedule I substance, amphetamines, narcotics, or any other substance that renders the driver incapable of safely operating a motor vehicle. However, there is an exception for a Schedule I drug if it was prescribed by a licensed medical practitioner.

Furthermore, drivers may not use or be under the influence of alcohol within 4 hours before going on duty or operating, use alcohol while on duty, or be on duty or operating a vehicle while possessing alcohol (unless the alcohol is part of the shipment). With regard to texting, drivers may not send or read text messages while driving a CMV, including while stuck in traffic or a light. Nonetheless, texting is allowed when legally parked or to contact an emergency service. Finally, drivers may not use a hand-held mobile phone while driving a CMV unless it is necessary to communicate with law enforcement officials or other emergency services.