By Jena Williams

You’ve got 14 hours to get your job done. Does it really matter when you drive, when you load, or when you take your break? Maybe…

A recent article by Soccolich, et al., suggests that how a truck driver spends his or her time during the 14-hour workday can matter a lot when it comes to safety. And it may not be as you think.

Their research showed that drivers were safer if they drove at the start of their 14-hour shift rather than doing task work (such as loading or maintenance) outside the truck for a few hours and then driving. If there was task work that needed to be done, then those drivers that took a one-hour break before beginning their drive were just as safe as those who started driving at the beginning of the shift.

How did they learn this? By using naturalistic data collection (observing drivers perform their regular work), the researchers determined that the length of time spent driving, whether 8 hours or 11 hours, did not impact safety as much as whether or not they performed other work  before the drive.

To categorize relative safety, the researchers developed criteria of safety-critical events (SCE) ­– crashes, near-crashes, crash-relevant conflicts, and unintentional lane deviations – to gauge the safety of the work day. Using various cameras, they observed driver tasks and SCE to determine how timing of tasks impacted SCE.

New data, new perspectives, and new decisions to be made….In truth, this research may or may not impact federal regulations, especially since there is often controversy surrounding different forms of data collection. However, as an employer, the more you know about what contributes to incidents and injuries with your workforce, the more you can organize your work to mitigate risk.

Link to Soccolich article:

FMCSA: Summary of HOS regulations:

FMCSA: Interstate Truck Driver’s Guide to Hours of Service

14-Hour Driving Window

This window is usually thought of as a “daily” limit even though it is not based on a 24-hour period. You are allowed a period of 14 consecutive hours in which to drive up to 11 hours after being off duty for 10 or more consecutive hours. The 14-consecutive-hour driving window begins when you start any kind of work. Once you have reached the end of this 14-consecutive-hour period, you cannot drive again until you have been off duty for another 10 consecutive hours, or the equivalent of at least 10 consecutive hours off duty.

Your driving is limited to the 14-consecutive-hour period even if you take some off-duty time, such as a lunch break or a nap, during those 14 hours.

FMCSA approach to naturalistic data collection:

Citation: Soccolich, S.A., et al., An analysis of driving and working hour on commercial motor vehicle driver safety using naturalistic data collection. Accid. Anal. Prev. (2012),