Knowledge based systems applications for traffic signal control

Knowledge Based Systems (KBS) applications to traffic engineering problems have been attempted. Applications range from systems designed to assist practicing engineers establish signal timing strategies to real-time systems for adaptive traffic signal control. This paper reports on a KBS prototype for Signal Control at Isolated Intersections (SCII). It represents an application of expert systems to adaptive signal control. The first generation of the prototype was developed at Arizona State University in 1987, and it was coded in LISP on a microcomputer. Major enhancements were implemented to SCII-1 to expand the prototype capabilities to different types of intersection geometrics and control modes, and the resulting product of this effort was the second-generation prototype SCII-2 Numerous tests were conducted to validate the prototype using field data and computer simulation. Tests conducted with computer simulation indicated the superiority of adaptive control in SCII-2 over the conventional pretimed controller.