Statistical Models of At-Grade Intersection Accidents-Addendum

FOREWORD

This report is an addendum to the published Report, FHWA-RD-96-125, titled Statistical Models of At-Grade Intersection Accidents. The objective of both reports is to develop accident prediction models relating total intersection accidents to highway design elements. The design elements considered include functional class, traffic flow, channelization, traffic control type, median, access control, terrain type, number of lanes, lane width, shoulder width, and lighting. While the previously published report is only for multi-vehicle accidents, this report includes all collision types (single and multi-vehicle). The result is a preliminary effort in the development of the Interactive Highway Safety Design Model (IHSDM), which is a Federal Highway Administration (FHWA) objective to develop a highway safety evaluation tool.

Based on retrospective analysis, several statistical modeling techniques were tried. Besides using innovative statistical techniques (e.g., Poisson and negative binomial regression models), five preliminary accident models were developed for at-grade intersections: (1) Rural, four-leg, STOP-controlled; (2) Rural, three-leg, STOP-controlled; (3) Urban, fourleg, STOP-controlled; (4) Urban, three-leg, STOP-controlled; and (5) Urban, four-leg, signalized.

Michael F. Trentacoste, Director

Office of Safety Research & Development