title: Exploring factors contributing to crash injury severity on rural two-lane highways.
abstract: OBJECTIVE
  Crash injury results from complex interaction among factors related to at-fault driver's behavior, vehicle characteristics, and road conditions. Identifying the significance of these factors which affect crash injury severity is critical for improving traffic safety. A method was developed to explore the relationship based on crash data collected on rural two-lane highways in China.
  
  
  METHODS
  There were 673 crash records collected on rural two-lane highways in China. A partial proportional odds model was developed to examine factors influencing crash injury severity owing to its high ability to accommodate the ordered response nature of injury severity. An elasticity analysis was conducted to quantify the marginal effects of each contributing factor.
  
  
  RESULTS
  The results show that nine explanatory variables, including at-fault driver's age, at-fault driver having a license or not, alcohol usage, speeding, pedestrian involved, type of area, weather condition, pavement type, and collision type, significantly affect injury severity. In addition to alcohol usage and pedestrian involved, others violate the proportional odds assumption. At-fault driver's age of 25-39years, alcohol usage, speeding, pedestrian involved, pavement type of asphalt, and collision type of angle are found to be increased crash injury severity.
  
  
  CONCLUSIONS
  The developed logit model has demonstrated itself efficient in identifying the effect of contributing factors on the crash injury severity.
authors.affiliation: School of Automobile, Chang'an University, Xi'an, Shaanxi, China. Electronic address: zhuanglinma@chd.edu.cn.
authors.forename: Zhuanglin
authors.initials: Z
authors.lastname: Ma
authors.affiliation: School of Automobile, Chang'an University, Xi'an, Shaanxi, China.
authors.forename: Wenjing
authors.initials: W
authors.lastname: Zhao
authors.affiliation: School of Automobile, Chang'an University, Xi'an, Shaanxi, China; Department of Civil and Environmental Engineering, New Jersey Institute of Technology, Newark, NJ, USA.
authors.forename: Steven I-Jy
authors.initials: SI
authors.lastname: Chien
authors.affiliation: Center of Transportation Research, The University of Tennessee, Knoxville, TN, USA.
authors.forename: Chunjiao
authors.initials: C
authors.lastname: Dong
mesh_terms: D000063:Accidents, Traffic / Q000706:statistics & numerical data*; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000428:Alcohol Drinking / Q000453:epidemiology; D002681:China / Q000453:epidemiology; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D018986:Motor Vehicles / Q000706:statistics & numerical data; D000069636:Pedestrians / Q000706:statistics & numerical data; D012424:Rural Population / Q000706:statistics & numerical data*; D015599:Trauma Severity Indices; D014887:Weather; D014947:Wounds and Injuries / Q000453:epidemiology*; D055815:Young Adult
keywords: Crash injury severity; Elasticity analysis; Partial proportional odds model; Rural two-lane highway; Traffic safety