title: The impacts of multiple rest-break periods on commercial truck driver's crash risk.
abstract: BACKGROUND
  Driver fatigue has been a major contributing factor to fatal commercial truck crashes, which accounted for about 10% of all fatal motor vehicle crashes that happened between 2009 and 2011. Commercial truck drivers' safety performance can deteriorate easily due to fatigue caused by long driving hours and irregular working schedules. To ensure safety, truck drivers often use off-duty time and short rest breaks during a trip to recover from fatigue.
  
  
  METHODS
  This study thoroughly investigates the impacts of off-duty time prior to a trip and short rest breaks on commercial truck safety by using Cox proportional hazards model and Andersen-Gill model.
  
  
  RESULTS
  It is found that increasing total rest-break duration can consistently reduce fatigue-related crash risk. Similarly, taking more rest breaks can help to reduce crash risk. The results suggest that two rest breaks are generally considered enough for a 10-hour trip, as three or more rest breaks may not further reduce crash risk substantially. Also, the length of each rest break does not need to be very long and 30min is usually adequate. In addition, this study investigates the safety impacts of when to take rest breaks. It is found that taking rest breaks too soon after a trip starts will cause the rest breaks to be less effective.
  
  
  CONCLUSIONS
  The findings of this research can help policy makers and trucking companies better understand the impacts of multiple rest-break periods and develop more effective rules to improve the safety of truck drivers.
authors: University of Massachusetts Lowell, Department of Civil and Environmental Engineering, 108 Falmouth Hall, One University Avenue, Lowell, MA 01854, United States. Electronic address: power.julian.chen@gmail.com.
authors: Chen
authors: C
authors: Chen
authors: University of Massachusetts Lowell, Department of Civil and Environmental Engineering, 108 Falmouth Hall, One University Avenue, Lowell, MA 01854, United States. Electronic address: yuanchang_xie@uml.edu.
authors: Yuanchang
authors: Y
authors: Xie
mesh_terms: D001334:Automobile Driving / Q000523:psychology* / Q000706:statistics & numerical data; D016022:Case-Control Studies; D003132:Commerce; D005221:Fatigue / Q000150:complications / Q000175:diagnosis; D006801:Humans; D015233:Models, Statistical; D018986:Motor Vehicles; D016272:Occupational Health / Q000331:legislation & jurisprudence; D016016:Proportional Hazards Models; D012146:Rest / Q000502:physiology*; D017751:Safety Management / Q000592:standards*; D012892:Sleep Deprivation / Q000175:diagnosis / Q000453:epidemiology; D014940:Work Schedule Tolerance; D000078329:Workforce; D016526:Workload / Q000523:psychology*
keywords: Driver fatigue; Hazard ratio; Hours-of-Service; Rest-break duration; Survival analysis