Analysis of Roadway and Environmental Factors Affecting Traffic Crash Severities

Death due to roadway crashes has been a leading cause of unnatural death in the United States for decades. The objective of this study is to identify and quantify the impacts of several key roadway and environmental factors to the traffic crash severities, and then recommend practices to emphasis on certain roadway types under certain environmental conditions to reduce the traffic fatalities and injuries. For this purpose, this study developed a logistic regression model to predict the odds and probability of a crash being a fatal/serious-injury crash under the combination of different roadway and environmental conditions. The study results showed that, road function class, crash location, road alignment, light condition, road surface condition, and speed limit has significant impacts on traffic crash severity. Higher crash severity are associated with rural roadways, major arterials, not at intersection locations, locations with curves, during nighttime when it is dark without street light, dry roadway conditions, and high speed limits.