Forensic Engineering Analysis of Roadway Geometry and Traffic Control

Abstract

When evaluating evidence for causative factors contributing to a motor vehicle collision, consideration should be given to roadway geometric or traffic control factors. Roadway geometry, clear zone, safety features, visibility obstructions, and traffic control devices and their placement may influence drivers’ behavior. Are the roadways involved properly designed and signed? The geometric design and traffic control requirements for special circumstances, such as highway construction zones, mixed-use paths, railway crossings, or low traffic volumes, may also present the potential for roadway issues. An evaluation of these potential contributing factors can open a Pandora’s box of opportunities for errors when an improper engineering analysis follows. This paper explores the topics that guide proper engineering analysis of roadway geometry and traffic control, including determining which design standards, policies, or guidelines apply and the proper application of the semantics in these documents. Additionally, this paper addresses recommendations contained in research concepts or reports versus requirements for the designer, the constructor, or the roadway owner. The discussion includes examples from past cases addressing the topics presented, providing a systematic approach to evaluating permanent or temporary roadway geometric or traffic control design for factors contributing to a collision event.