Conference Proceeding

Effect of Driving Breaks and 34-hour Recovery Period on Motor Carrier Crash

  • Kun-Feng Wu (Pennsylvania State University, University Park, PA)
  • Paul Jovanis (Pennsylvania State University, University Park, PA)


This research seeks to contribute to our knowledge of the relationship between truck driver hours of service and motor carrier crash odds. Data were collected from less-than-truckload carriers in 2004-05 and 2010 including the precise hours of service for crash-involved drivers and a random sample of noncrash involved drivers. Time-dependent logistic regression models were formulated to study the probability of a crash after a certain number of hours driving, given survival until that time. In addition to driving time during a trip, the models included presence of 34 hours consecutively off-duty immediately prior to the trip of interest and the use of breaks from driving by the driver. Multi-day driving patterns, developed using cluster analysis, cover the 7 days prior to the day of interest in an attempt to capture the effect of the pattern of driving over many days. Among the findings of this research are: (1) Driving hours 6 through 11 show continuous increases in the crash risk, (2) substantial and consistent benefits for drivers who take breaks compared to drivers who drive without breaks; benefits ranged from 34 to 47 percent reduction in crash odds, depending on the number of breaks taken, (3) drivers who had 34 hours or more off-duty immediately prior to the measurement period had a nearly 43 percent increase in crash odds, and (4) additional investigation shows that drivers have the greatest difficulty immediately after returning from the extended time off; the effect then diminishes with time.

How to Cite:

Wu, K. & Jovanis, P., (2011) “Effect of Driving Breaks and 34-hour Recovery Period on Motor Carrier Crash
 Odds”, Driving Assessment Conference 6(2011), 606-613. doi:

Rights: Copyright © 2011 the author(s)

Publisher Notes

  • FMCSA Commercial Vehicle Operations Student & Young Research Awards

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Published on
30 Jun 2011
Peer Reviewed