title: A preliminary analysis of traffic crashes by out-of-state drivers.
abstract: OBJECTIVE
  This study was designed to investigate the relationship between the involvement of out-of-state drivers in fatal crashes and each US state's fatality rate per distance driven.
  
  
  METHODS
  Two analyses were performed. In the first analysis, we examined the percentages of out-of-state drivers among those involved in fatal crashes using the data from the Fatal Analysis Reporting System (FARS). In the second analysis, we correlated these percentages with the states' fatality rates per distance driven. Both analyses used the data for 2008.
  
  
  RESULTS
  There are two main findings of this study. First, there is wide variability across the 50 states in the percentage of all drivers involved in fatal crashes who were out-of-state drivers, with a minimum of 5.0 percent in California and a maximum of 41.2 percent in Wyoming. Second, there is a positive correlation between this percentage and the corresponding fatality rate per distance driven.
  
  
  CONCLUSIONS
  There are two main findings. First, states vary greatly in terms of the involvement of out-of-state drivers in fatal crashes. Second, the states with higher fatality rates tend to have higher percentages of out-of-state drivers among the persons involved in fatal crashes. However, whether this relationship is causative (ie, the extent of the involvement of out-of-state drivers among the persons involved in fatal crashes influences the states' overall fatality rates) or noncausative (eg, there is more out-of-state traffic in states with higher fatality rates) cannot be ascertained from the available data. The missing data concern the relative distance driven in each state by out-of-state drivers.
authors.affiliation: The University of Michigan Transportation Research Institute, Ann Arbor, Michigan 48109-2150, USA. sivak@umich.edu
authors.forename: Michael
authors.initials: M
authors.lastname: Sivak
authors.forename: Brandon
authors.initials: B
authors.lastname: Schoettle
mesh_terms: D000063:Accidents, Traffic / Q000401:mortality*; D001334:Automobile Driving / Q000706:statistics & numerical data*; D016208:Databases, Factual; D006801:Humans; D012307:Risk Factors; D014481:United States / Q000453:epidemiology