Incident Clustering: Diagnostic Approach for Assessing Usability of Intersections and Other Road Sites

Abstract

During the course of an FHWA-sponsored research project, driver errors in crashes and near-crashes (i.e., critical incidents) were investigated, and an analysis approach was developed with which to identify infrastructure-related and non-infrastructure-related problems at intersections and other roadway sites. Referred to as a specific site critical incident analysis, this analysis approach consisted of four general steps: ( a) selection of a site, ( b) careful review of the site's critical-incident data, ( c) determination of the potential critical-incident contributing factors, and ( d) identification of incident clusters. An incident cluster is a group of critical incidents with similar characteristics that occur at the same location. From these incident clusters, researchers gained insight into potential infrastructure-related and non-infrastructure-related causal factors associated with critical incidents and, subsequently, could redesign solutions. An overview is presented of the incident cluster approach, as is an example analysis conducted for the driver error project.