The rural two-lane highway in the Southeastern United States is frequently associated with a disproportionate number of serious and fatal crashes and as such remains a focus of considerable safety research. The Georgia Department of Transportation spearheaded a regional fatal crash analysis toidentify various safety performances on two-lane rural highways and offerguidance for identifying suitable countermeasures to mitigate fatal crashes. The fatal crash data used in this study were compiled from Alabama, Georgia, Mississippi, and South Carolina. The database, developed for an earlier study, included a total of 557 randomly selected fatal crashes from the years 1997 and/or 1998 (varied per state). Each participating state identified the candidate crashes and performed physical or video site visits to construct crash databases with enhance site-specific information. Motivated by the hypothesis that single- and multiple-vehicle crashes arise under fundamentally different circumstances, the research team applied binary logit models to predict the probability that a fatal crash is a single-vehicle crash given roadway design characteristics, roadside environment features, and traffic conditions proximal to the crash site. The study also included an historic crash trend analysis to provide background on Southeastern US fatal crashes. A wide variety of factors appears to influence or be associated with single-vehicle fatal crashes. These influential factors include location, lane width, shoulder width and type, horizontal curve direction, the presence of crest vertical curves, horizontal and vertical geometric interactions, roadside hazard ratings, traffic volume, driveway type, lighting conditions, and time of crash.
Abstract