Characteristics of drivers who cause run-off-road-crashes on Ohio roadways

A vehicle that leaves its travel lane at a non-intersection location and collides with another vehicle or with a fixed object or overturns is considered to be involved in a run-off-road (ROR) crash. ROR crashes also known as roadway departure crashes, and these include head-on crashes, crashes that occur due to lane shifts, and crashes where the vehicle leaves its designated travel lane. The main objective of this study was to identify the significant factors that lead to these types of crashes. Crash data used in this study were obtained from the Ohio Department of Public Safety for a five-year period from 2008 to 2012. The classification tree modeling was used in this study to investigate the significant predictor variables of crash severity of ROR crashes. In addition, this thesis study developed two models, the ROR crashes model and the non-run-off-road (NROR) crashes model. The NROR crashes model used crash data for drivers who were at fault when their crash incidents occurred and for ROR crashes; it was assumed that all drivers in this category were at fault of causing the crashes. The ROR model identified nine variables, which include road condition, collision type, alcohol related, posted speed limit, speed related, crash type, vehicle type, gender, and age. The NROR crashes model has six significant predictor variables including collision type, posted speed limit, speed related, road condition, alcohol related, and vehicle type