CONCEPTUAL DEVELOPMENT OF EXPOSURE MEASURES FOR EVALUATING HIGHWAY SAFETY

An overview of exposure measures such as distance, time, traffic volume, vehicle hours, and vehicle miles used in the past for evaluating accidents on highways and intersections is presented. Their inadequacy and insufficiency are discussed. The conceptual exposure measures for evaluating highway safety are presented for the sections between signalized intersections and at intersections. Exposure measure is suggested to include all highway and traffic elements that affect accidents in the highway-traffic-environment system. Also suggested is that the number of accidents is the square of the exposure measure that operates in the highway-traffic-environment system. (Author)