Title

CITY OF SAN DIEGO'S MASTER TRAFFIC SIGNAL CONTROL SYSTEM

Document Type

Journal Article

Publication Date

1989

Subject Area

operations - traffic, place - cbd, mode - bus

Keywords

Traffic signal controllers, Traffic control systems, Traffic control, Software, San Diego (California), Electronic traffic controls, Downtowns, Data transmission systems, Data communications, Costs, Controllers (Traffic signal control equipment), City centers, Central business districts

Abstract

A master traffic control system for 150 signals was implemented in the central business district of San Diego in 1984. The central system is controlled by a Perkin-Elmer model 3230 computer with two megabytes of memory driven by Enhanced Urban Traffic Control System (UTCS) software. A front-end communications processor is used to do actual second-by-second data transmission. Data between the central computer and the front-end communications processor are transferred in blocks via two 8-kilobyte buffers in the central processor. Details of the software, communications network, and intersection controllers are described. The trolley preemption for the two light rail transit lines is described. System costs are discussed, and future plans are noted.