Abstract
This paper describes the application of expert systems in traffic-actuated control at isolated signalized intersections. The expert system EXACT (EXpert system of ACtuated control for Traffic at isolated intersections) was developed to assist traffic engineers in selecting the appropriate type of traffic-actuated controller and its associated features, the type of detector and its configuration, and time settings at a particular intersection. EXACT was structered to handle both design and operational problems. The first steps of EXACT's development, including variable identification, shell selection, knowledge acquisition, and knowledge representation, are presented in detail in this paper.