title: Differences in injury severities between 2-vehicle and 3-vehicle crashes.
abstract: OBJECTIVE
  In traditional injury severity-related studies, 2-vehicle and 3-vehicle crashes are typically considered in a combinatory manner and thus the injury casual factors for these 2 crash types are implicitly assumed to be the same. This article attempts to investigate the potential discrepancy between 2- and 3-vehicle crash severities with the aid of a continuation ratio logit model with the property of partial proportional odds.
  
  
  RESULTS
  The modeling results show that there are a number of significant differences between 2- and 3-vehicle crash injury severities in terms of the contributing factors, the magnitude of impact, and even the direction of effects.
  
  
  CONCLUSIONS
  The research illustrates that a series of environmental and crash factors (e.g., rear-end straight crashes, urban roadways, alcohol usage, and different driving cohorts) are statistically significant in interpreting the disparity of coefficients between 2- and 3-vehicle crash injury severity models. It raises awareness that the combined analysis of 2- and 3-vehicle crashes should be exercised with caution, particularly when safety research targets crashes with less severe injuries.
authors.affiliation: a School of Transportation and Logistics , Southwest Jiaotong University, National United Engineering Laboratory of Integrated and Intelligent Transportation , Chengdu , China.
authors.forename: Xinguo
authors.initials: X
authors.lastname: Jiang
authors.forename: Haitao
authors.initials: H
authors.lastname: Zheng
authors.forename: Yanjun
authors.initials: Y
authors.lastname: Qiu
authors.forename: Wenbo
authors.initials: W
authors.lastname: Fan
mesh_terms: D000063:Accidents, Traffic / Q000706:statistics & numerical data*; D006801:Humans; D016015:Logistic Models; D018986:Motor Vehicles / Q000706:statistics & numerical data*; D012449:Safety; D015599:Trauma Severity Indices; D014947:Wounds and Injuries / Q000453:epidemiology*
keywords: 2-vehicle crashes; 3-vehicle crashes; continuation ratio logit; injury severity