Signal control at isolated intersection (scii) is a knowledge-based expert system prototype. 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. The second-generation scii can handle three types of intersection geometries. At the end of each signal cycle, scii determines the performance of the controller operation during that cycle. In case of an unsatisfactory performance, scii determines the appropriate cycle length, phasing pattern, and split. It also updates the cycle length and phasing scheme based on traffic demand. Different tests validated and calibrated the prototype using a simulation approach. A 20-min traffic volume data set was used to simulate a pretimed controller, an actuatedcontroller, and the operations suggested by scii. The tests demonstrated the potential of this prototype to reduce delay at isolated intersections. This paper appears in transportation research record no. 1324, Communications, traffic signals, and traffic control devices1991
Abstract