The purpose of this study was to determine the most effective method of identifying hazardous locations for on-site investigations. To decrease the possible effect of random or spurious accidents on the identification of hazardous locations, a 0.3-mile (0.48-km) segment was chosen along with 1- and 2-year periods for accumulating and comparing accident data. An optimal method for identifying hazardous locations and sections was determined to be one which (1) maximizes benefits from improvements, (2) identifies locations with critically high accident rates, and (3) identifies potential hazards. A sample of 170 locations was used to compare several location-identification methods. The procedure recommended combines a Number Method, EPDO Method, Rate-Quality Control Method, and objective input from citizens and state police. This procedure should be used to identify hazardous spots 0.3 mile (0.48 km) long and sections 1 and 3 miles (1.61 and 4.83 km) long which should be investigated in the field. A detailed plan for implementing such a procedure is also proposed.

Report Date


Report Number

No. 392

Digital Object Identifier



The contents of this report reflect the views of the author who is responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the Bureau of Highways. This report does not constitute a standard, specification, or regulation.