Expert System for Traffic Control in Work Zones

The development of a prototype knowledge‐based expert system (KBES) for selecting appropriate traffic control strategies and management techniques around highway work zones is described. The knowledge base of this KBES is derived from a literature survey on existing techniques and approaches for handling traffic around highway work zones and from interviews with selected experts in charge of the planning and design of traffic control strategies for work zones in Virginia. The developmental process includes steps in formulating the problem and developing an expert system: identification, conceptualization, implementation, and testing. The resulting EXSYS prototype system, TRANZ, is described. TRANZ knowledge base consists of 141 rules. A decision tree is developed to provide an aid to resolve erroneous recommendations by the system. This model shows the range of control options and associated condition variables that intersect to produce control requirements. This EXSYS prototype system is the initial stage in the development of an expert system. Additional testing, validation, and verification, necessary before the system can be recommended for professional applications, is described. Traffic management in work zones is an ideal application area for expert systems, thereby giving TRANZ a high probability of acceptance when the system is fully developed and operating as intended.