Signal Design at lsolated lntersecaions Using Expert Systems Technology

The procedural steps for developing an expert system for designing signals at isolated intersections are described and the most important development issues for each step are discussed. The steps include problem analysis and definition, preliminary prototype specification, knowledge acquisition strategy development, prototype development plan, knowledge extraction, knowledge representation, tool/paradigm selection, prototype development, testing and refinement, and verification and validation. The result is a user friendly expert system that can be used by practicing engineers to design signalization for isolated intersections; for intersections that already exist but no control configuration such as detector placement, phasing, or timing has not been determined yet; and, for intersections that already have all the required features but need to he updated and enhanced.