Evaluating and Adaptive Signal Control System in Gresham

Cities and Counties are faced with increasing traffic congestion due to rapidly increasing population. Like many agencies, the City of Gresham has struggled with how to manage the increasing congestion with limited funds for major roadway widening projects. Gresham has recognized the need to optimize existing system capacity to get the most out of their current transportation system infrastructure investment. In 2005, the City of Gresham, in cooperation with numerous agencies in the Portland metropolitan area, evaluated a variety of signal control systems including traditional time-of-day coordination, traffic responsive, and adaptive signal control systems. Based on that evaluation, the steering committee selected and deployed the SCATS adaptive signal control system on Burnside Road between Eastman Parkway and Powell Boulevard. The Burnside corridor in Gresham, OR is a 5 lane major arterial that carries approximately 38,000 ADT. Burnside serves as a main through route connecting I-84 to OR 26 and Mt. Hood. The SCATS system has been integrated with the existing shared regional traffic signal system and is available for expansion to other jurisdictions in the region. This paper describes the process used to evaluate the results of the adaptive signal control system and how they compare to the original project objectives. The evaluation compares changes in travel time, delay, stops and fuel consumption associated with “free” (uncoordinated), time-of-day coordinated and the new adaptive signal system on Burnside Road. This paper should be of interest to other state and local agencies interested in trying to optimize existing arterial capacity