Analysis of left-turn crash injury severity by conflicting pattern using partial proportional odds models

    Authors

    X. S. Wang;M. Abdel-Aty

    Comments

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    Abbreviated Journal Title

    Accid. Anal. Prev.

    Keywords

    signalized intersection; left-turn crash; conflicting pattern; crash; injury severity; partial proportional odds model; significant factor; SIGNALIZED INTERSECTIONS; VEHICLE; Ergonomics; Public, Environmental & Occupational Health; Social; Sciences, Interdisciplinary; Transportation

    Abstract

    The purpose of this Study is to examine left-turn crash injury severity. Left-turning traffic colliding with opposing through traffic and with near-side through traffic are the two most frequently occurring conflicting patterns among left-turn crashes (Patterns 5 and 8 in the paper, respectively), and they are prone to be severe. Ordered probability models with either logit or probit function is commonly applied in crash injury severity analyses; however, its critical assumption that the slope coefficients do not vary over different alternatives except the cut-off points is Usually too restrictive. Partial proportional odds models are generalizations of ordered probability models, for which some of the beta coefficients can differ across alternatives, were applied to investigate Patterns 5 and 8, and the total left-turn crash injuries. The results show that partial proportional odds models consistently perform better than ordered probability models. By focusing on specific conflicting patterns, locating crashes to the exact crash sites and relating approach Variables to crash injury in the analysis, researchers are able to investigate how these variables affect left-turn crash injuries. For example, opposing through traffic and near-side crossing through traffic in the hour of collision were identified significant for Patterns 5 and 8 crash injuries, respectively. Protected left-turn phasing is significantly correlated with Pattern 5 Crash injury. Many other variables in driver attributes, vehicular characteristics, roadway geometry design, environmental factors, and crash characteristics were identified. Specifically, the use of the partial proportional formulation allows a much better identification of the increasing effect of alcohol and/or drug use on crash injury severity, which previously was masked using the conventional ordered probability models. (C) 2008 Elsevier Ltd. All rights reserved.

    Journal Title

    Accident Analysis and Prevention

    Volume

    40

    Issue/Number

    5

    Publication Date

    1-1-2008

    Document Type

    Article

    Language

    English

    First Page

    1674

    Last Page

    1682

    WOS Identifier

    WOS:000259739400006

    ISSN

    0001-4575

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