The Federal Motor Carrier Safety Administration (FMCSA) specifically regulates how many hours a commercial truck driver can drive during a 24-hour period. 

  • At the start of a work shift a driver may not drive without first taking 10 consecutive hours off duty.
  • A driver may not drive after a period of 14 consecutive hours after coming on duty following 10 consecutive hours off duty
  • A driver may only drive a total of 11 hours of the 14 hours allowed in the section above
  • Driving is not permitted if more than 8 hours of driving time have passed without at least a consecutive 30-minute interruption in driving status.
  • If the employer operates commercial vehicles 7 days a week, a driver may not be on duty for more than 70 hours in any period of 8 consecutive days.
  • Any period of 7 consecutive days may end with the beginning of an off duty period of 34 or more consecutive hours.

There are a couple of exceptions that generally apply to these restrictions.  First if a driver encounters an adverse driving condition which does not allow him/her to safely complete the run within the maximum driving time he may be permitted to drive for an additional two hours beyond the maximum allowable hours. 

Adverse driving condition means snow, ice, sleet, fog or other adverse weather conditions or unusual road or traffic conditions that were not known, or could not reasonably be known, to a driver immediately prior to the beginning of the duty.

Also, in case of any emergency, a driver may complete his/her run without being in violation of the hours limitation if such run reasonably could have been completed absent the emergency.