Traffic conflict standards for intersections

This paper describes the application of the traffic conflict technique to e stimate, traffic safety at intersections. Using data collected from 94 conf lict surveys, traffic conflict frequency and severity standards for signali zed and unsignalized intersections have been established. These standards a llow for the relative comparison of the conflict risk at various intersecti ons. An Intersection Conflict Index (ICI) measure was developed to summariz e conflict risk and provide an indication regarding the relative risk of be ing involved in a conflict at an intersection. Zn addition, regression anal ysis was used to develop predictive models which relate the number of traff ic conflicts to traffic volume and accidents. The regression analysis resul ts indicate that: (i) the average hourly conflict rate (AHC) and the averag e hourly severe conflict rate (AHC 4+) correlated reasonably well with traf fic volume for both signalized and unsignalized intersections, and (ii) str ong relationships between accidents and conflicts were obtained for signali zed intersections only. These research efforts are expected to further enha nce the usefulness of the traffic conflict technique as a tool to evaluate the safety of intersections. Finally, a case study is presented as an examp le of the usefulness of traffic conflict analysis.