Campus Units

Civil, Construction and Environmental Engineering, Statistics

Document Type

Article

Publication Version

Accepted Manuscript

Publication Date

3-2018

Journal or Book Title

Analytic Methods in Accident Research

Volume

17

First Page

32

Last Page

46

DOI

10.1016/j.amar.2018.03.001

Abstract

Urban midblock crashes are influenced mainly by traffic operation and roadway geometric features. In this paper, 10-year crash data from 1,506 directional urban midblock segments in Nebraska were analyzed using the multivariate random parameters zero-inflated negative binomial model to account for unobserved heterogeneity produced by correlations across segments, correlations across crash collision types, excessive zero crashes, and over dispersion. The multivariate random parameters zero-inflated negative binomial model was superior to many common crash frequency models in terms of both goodness of fit and prediction accuracy. Compared with the multivariate fixed parameters zero-inflated negative binomial model, the multivariate random parameters zero-inflated negative binomial model identified fewer key influencing factors and revealed segment-specific effects of these factors on different crash types. It showed that the number of lanes, annual average daily traffic per lane, and segment length might have non-positive effects on crash frequencies. Segments with a speed limit of 45 mph had fewer crashes than did those with lower speed limits, and there were fewer crashes on the segments in Omaha than on those in Lincoln. It was also found that neither the presence of a shoulder, on-street parking, or one-way traffic, nor lane width had significant influences on crash frequencies. These findings are informative for transportation agencies to take correct and efficient measures to accommodate diverse transportation demands without reducing traffic safety. By contrast, the fixed parameters model produced results consistent with intuition, but the results were insufficient to provide actionable recommendations.

Research Focus Area

Transportation Engineering

Comments

This is a manuscript of an article published as Liu, Chenhui, Mo Zhao, Wei Li, and Anuj Sharma. "Multivariate random parameters zero-inflated negative binomial regression for analyzing urban midblock crashes." Analytic Methods in Accident Research 17 (2018): 32-46. DOI: 10.1016/j.amar.2018.03.001. Posted with permission.

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Copyright Owner

Elsevier Ltd.

Language

en

File Format

application/pdf

Available for download on Friday, March 01, 2019

Published Version

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