Ask Risk Control: Hours-of-Service exceptions during adverse conditions

Trucker reads on his tablet before starting his day


Question:How does the hours-of-service (HOS) exception work during adverse driving conditions?

Answer: According to Federal Motor Carrier Safety Administration (FMCSA) 49 CFR Part 395.1(b)(1), the rule allows a driver to have extra time to complete their day after encountering unexpected delays caused by weather or traffic. A driver may extend both driving and on-duty limits by two hours. This is a change from the old rule, which permitted drivers to extend their driving limit, not their on-duty limit. Truck drivers subject to the 14-hour limit will be most affected by the change.

So what’s the benefit of the new rule?

With the expanded hours, more drivers will be eligible to use the exception to wait out unexpected weather or traffic conditions, rather than trying to “race the clock” to complete the run. Drivers will have an added cushion of on-duty time when using the exception. All driving (up to 13 hours for truck drivers) will need to be done within 16 consecutive hours for truck drivers.

Note that the allowable uses of this exception remain relatively narrow. See the definition of Adverse Driving Conditions in §395.2. Motor carriers are obligated to make sure the adverse conditions were unknowable at the time of dispatch. Motor carriers and drivers should check traffic and weather conditions before starting a run. Motor carriers should make sure drivers are aware that they cannot use this exception for routine weather or traffic delays. The delay must be unexpected, and it cannot be due to normal rush-hour traffic, vehicle breakdowns, loading or unloading delays, or the inability to find parking.

Overall, this exception is rare to use. Motor carriers may not qualify to use the adverse driving conditions exception. If the motor carrier feels it has received the violation incorrectly, it has the option to submit a DataQ. However, before submitting the DataQ, consider the following:

  • Did the driver note the exception on the log?
  • Did the driver pass other available parking locations?
  • Was the motoring public warned of the incident before encountering the slowdown?


  • Train operations staff on the HOS exception for adverse conditions.
  • Monitor weather and traffic reports to ensure drivers are aware of adverse conditions.
  • Train drivers how to enter this exception into their electronic logging devices.
  • Develop an internal process for using and documenting the HOS exception for adverse conditions.


The information in this article is provided as a courtesy of Great West Casualty Company and is part of the Value-Driven® Company program. Value-Driven Company was created to help educate and inform insureds so they can make better decisions, build a culture that values safety, and manage risk more effectively. To see what additional resources Great West Casualty Company can provide for its insureds, please contact your safety representative, or click below to find an agent.

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