Impact of Hours-of-Service regulations on truck drivers' work and sleep time

Background/purpose: This study is to assess changes in truck drivers' work and sleep time before and after the implementation of the revised Hours-of-Service regulations on January 4, 2004.

Methods: American Time Use Survey from 2003 to 2006 was used. ATUS is a representative sample of persons age 15 or older living in U.S. households. It uses telephone interviews to ask participants about the sequential activities they engaged in on the previous day. In this study durations for each activity were computed. Subjects in this analysis included full-time truck drivers. Data analysis was conducted after February 2009.

Results/Outcomes: This study suggests that there is an increasing trend in truck drivers daily work hours from 2003 to 2006. By 2006, truck drivers worked one hour/day more on weekdays and 3.4 hours/day more on weekends compared to 2003. Truck drivers slept one hour/day more on a working weekday in 2004 compared to 2003, however the increased sleep hours gradually declined by 2006. There was also an increasing trend in percentage of truck drivers who worked more than 11 hours. The percentage of truck drivers who worked 14 hours/day increased in 2005 and 2006 (9% in 2005 and 7% in 2006).

Conclusions: Truck drivers' work and sleep time have great implications on traffic safety. If truck drivers work hours are increasing significantly on a working day to compensate for the 34 hours off-duty HOS regulations, then this may increase fatigue and risk of crashes.