THE HIGHWAY SAFETY EXPERT SYSTEM: DIAGNOSING ACCIDENT PRONE LOCATIONS

Abstract

This paper describes the diagnosis phase of a highway safety expert system. The overall objective of the expert system is to provide highway safety officials with an efficient tool to identify accident prone locations and then quickly and reliably advise on the appropriate countermeasure(s) based on an analysis of the accident and roadway environment data. The system has three basic phases: detection, diagnosis and remedy. In the diagnosis phase a knowledge-based system is developed to identify the causes and the contribution factors of safety problems at accident prone locations and to suggest appropriate countermeasures. It is shown that the knowledge-based approach best-suits the diagnosis process since it involves a great deal of judgment and experience by the safety engineer. The paper describes different steps involved in developing the diagnosis phase including: knowledge acquisition, problem solving strategy, system features, uncertainty handling, and system verification and validation. The output of the diagnosis phase is a set of applicable countermeasures for each accident prone location and the degree of belief in each countermeasure. The knowledge-based system was validated using several case studies which demonstrated satisfactory results.