The objective of this report was to develop a procedure for the collection and use of traffic conflict data. Data were collected at five intersections to determine characteristics of conflicts. Observer reliability was found to be excellent. Traffic volumes accounted for only about 30 percent of the variation in numbers of conflicts. At one intersection, repeatability of conflict numbers, rates, and types was found to be very good. A total of 6,535 conflicts and 2,957 benign weaves were observed at the test sites.

Based on the data, recommendations were made for collecting data during three peak hours at each site. Revised conflict data sheets were developed for signalized and nonsignalized intersections. The conflict diagram is illustrated and recommended for use. Collection of conflict data is recommended during inspections of suspected hazardous locations.

Report Date


Report Number

No. 490

Digital Object Identifier



The contents of this report reflect the views of the author who ls 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.