Title

Modeling left-turn crash occurrence at signalized intersections by conflicting patterns

Authors

Authors

X. S. Wang;M. Abdel-Aty

Comments

Authors: contact us about adding a copy of your work at STARS@ucf.edu

Abbreviated Journal Title

Accid. Anal. Prev.

Keywords

signalized intersection; left-turn crashes; conflicting patterns; approach level model; negative binomial; generalized estimating; equations; LONGITUDINAL DATA-ANALYSIS; Ergonomics; Public, Environmental & Occupational Health; Social; Sciences, Interdisciplinary; Transportation

Abstract

In order to better understand the underlying crash mechanisms, left-turn crashes occurring at 197 four-legged signalized intersections over 6 years were classified into nine patterns based on vehicle maneuvers and then were assigned to intersection approaches. Crash frequency of each pattern was modeled at the approach level by mainly using Generalized Estimating Equations (GEE) with the Negative Binomial as the link function to account for the correlation among the crash data. GEE with a binomial logit link function was also applied for patterns with fewer crashes. The Cumulative Residuals test shows that, for correlated left-turn crashes, GEE models usually outperformed basic Negative Binomial models. The estimation results show that there are obvious differences in the factors that cause the occurrence of different left-turn collision patterns. For example, for each pattern, the traffic flows to which the colliding vehicles belong are identified to be significant. The width of the crossing distance (represented by the number of through lanes on the opposing approach of the left-turning traffic) is associated with more left-turn traffic colliding with opposing through traffic (Pattern 5), but with less left-turning traffic colliding with near-side crossing through traffic (Pattern 8). The safety effectiveness of the left-turning signal is not consistent for different crash patterns; "protected" phasing is correlated with fewer Pattern 5 crashes, but with more Pattern 8 crashes. The study indicates that in order to develop efficient countermeasures for left-turn crashes and improve safety at signalized intersections, left-turn crashes should be considered in different patterns. (c) 2007 Elsevier Ltd. All rights reserved.

Journal Title

Accident Analysis and Prevention

Volume

40

Issue/Number

1

Publication Date

1-1-2008

Document Type

Article

Language

English

First Page

76

Last Page

88

WOS Identifier

WOS:000253346500010

ISSN

0001-4575

Share

COinS