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Title:

Freeway Crash Analysis Considering Monthly Variation in Traffic Volumes and Weather Conditions Using Time Series Random Effect Negative Binomial Models

Accession Number:

01664149

Record Type:

Component

Abstract:

The research investigated the effects of monthly traffic and weather conditions on traffic crash counts and considered the correlations between these factors. Time series random effect negative binomial models were estimated for total crashes, major types of crashes (front-to-rear, sideswipe-same-direction, and fixed-object), severe crashes (i.e., fatal and injury crashes) and non-injury crashes (i.e., property-damage-only crashes). Major findings are that variations in monthly traffic volumes, roadway geometry, and weather conditions explain much of the variations in monthly traffic crashes. Higher monthly traffic volumes, narrower inside or outside shoulder widths, lower temperature, more heavy fog days, increased snowfall, and lower wind speed were found to be associated with higher monthly crashes. Time series effect exists in the panel monthly data for most types of crashes. Taking into account this effect improves model estimation results. When the raw weather measures are highly correlated, using dimension reduction techniques helps to extract more interpretable weather factors. By considering the interaction effects between traffic volumes and weather components, additional findings were found. Compared to high traffic volume freeways, low traffic volume freeways are more influenced by snowfall and less affected by temperature. The findings of this research could help researchers and general readers gain better understanding of the effects of monthly weather conditions on freeway crashes and give engineers practical guidelines on improving freeway safety.

Supplemental Notes:

This paper was sponsored by TRB committee ANB20 Standing Committee on Safety Data, Analysis and Evaluation.

Report/Paper Numbers:

18-05263

Language:

English

Authors:

Zhao, Shanshan
Wang, Kai
Liu, Chenhui
Jackson, Eric

Pagination:

4p

Publication Date:

2018

Conference:

Transportation Research Board 97th Annual Meeting

Location: Washington DC, United States
Date: 2018-1-7 to 2018-1-11
Sponsors: Transportation Research Board

Media Type:

Digital/other

Features:

References (7)

Subject Areas:

Data and Information Technology; Highways; Safety and Human Factors

Source Data:

Transportation Research Board Annual Meeting 2018 Paper #18-05263

Files:

TRIS, TRB, ATRI

Created Date:

Jan 8 2018 11:19AM