01478380

Component

Understanding the relationships between traffic flow characteristics and crash risk under adverse weather conditions will help highway agencies develop proactive safety management strategies to improve traffic safety in adverse weather conditions. The primary objective of this study is to develop separate crash risk prediction models for different weather conditions. The crash data and traffic data used in this study were collected on the I-880 North freeway in California, United States in 2008 and 2010. This study considers three different weather conditions: clear weather, rainy weather and reduced visibility weather. The preliminary analysis showed that there was some heterogeneity in the risk estimate for traffic flow characteristics by weather conditions, and that the crash risk prediction model for all weather conditions cannot capture the impacts of the traffic flow variables on crash risk under adverse weather conditions. The Bayesian logistic regressions were applied in this study to link the likelihood of crash occurrence with various traffic flow characteristics under different weather conditions. The model estimation results showed that the traffic flow characteristics contributing to crash risk were found to be different across different weather conditions. The speed difference between upstream and downstream station was found to be significant in each crash risk prediction model. And the large speed difference between upstream and downstream station in reduced visibility weather has the largest impacts on crash risk, followed by that in rainy weather. The receiver operating characteristic (ROC) curves were further developed to evaluate the prediction performance of the crash risk prediction model under different weather conditions. It was found that the prediction performance of the crash risk model for clear weather was better than that of the crash risk model for adverse weather conditions.

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

01470560

13-4996

English

17p

2013

Transportation Research Board 92nd Annual Meeting

Digital/other

Figures; References; Tables

Crash risk forecasting; Freeways; Highway safety; Logistic regression analysis; Rain; Traffic flow; Visibility; Weather conditions

California

Highways; Operations and Traffic Management; Safety and Human Factors; I71: Traffic Theory; I80: Accident Studies

Transportation Research Board Annual Meeting 2013 Paper #13-4996

TRIS, TRB, ATRI

Feb 5 2013 12:57PM