Rainfall impacts on traffic safety: rain-related fatal crashes in Texas

Abstract

This study uses fatal crash data and geospatial analysis to examine the temporal and spatial distribution of rain-related fatal crashes in Texas from 1982 to 2011. The data were obtained from the Fatality Analysis Reporting System maintained by the National Highway Traffic Safety Administration. The Getis–Ord Gi*(di) statistic was used to identify spatial clustering patterns of rain-related fatal crashes and their correlation with rainfall and compare them to spatial patterns of other crashes. The spatial statistical analysis reveals spatial patterns for rain-related crashes that are clustered in different areas at different levels of confidence. The temporal variability of raw and normalized fatal crashes and rain-related crashes was also investigated at the state level. Although the population of Texas increased by more than 67% over the study period, with a corresponding increase in the number of vehicles, the fatal crashes and rain-related crashes in Texas did not increase but decreased instead. Results suggest that rain is a contributor to crashes in few counties but at less than 95% confidence in some of the wetter counties. These counties should be the focus of further research and detailed analysis to identify underlying crash contributing factors such that safety countermeasures can be developed.