Computers: Microcomputers promise less stop, more go: Designers off urban traffic-control systems propose hierarchical schemes to enhance local control, reliability, and maintainability

Designers of urban traffic-control systems propose hierarchical schemes to enhance local control, reliability, and maintainability. The multilevel distributed system approach consists of local intersection controllers, master controllers, and network processors, and provides for communication among these geographically isolated devices. Although within the context of the entire hierarchical system these devices are interdependent, each retains the ability to control its defined functions independently.