Adaptive Signal Control Technology Pilot

About the Program

Category: Transportation (Best in Category)

Year: 2018

Montgomery County took on a project to develop, select and deploy Adaptive Signal Control Technology (ASCT) as part of their Traffic Signal System Modernization (TSSM) project. Adaptive control is a form of traffic signal operation in which some or all of the signal timing parameters are modified in response to real-time changes in the traffic conditions in order to optimize an objective function (progression, throughput, stops, delays, operating cost, emissions, etc.). The purpose of providing adaptive control in the County is to overcome the increased delay due to unpredictability of traffic fluctuations as a result of increased congestion in the area. The variability and unpredictability of traffic demand on arterial systems often outpace the ability of an operating agency to update signal timings so that signalized intersections operate efficiently and do not cause congestion and delays to motorists and pedestrians. ASCT contains an on-line model which together with vehicle detection accurately describes traffic flow behavior in real-time. Its timing plans and performance are evaluated by an algorithm that searches for the optimum combination of timing settings based on established objectives. The derived timing changes are implemented on a continuous basis in small but frequent increments to avoid drastic disruption to the traffic flow. ASCT generates a large amount of traffic sensor data along with the traffic signal control status and timing adjustments that are used to monitor and verify operations. Information collection, analysis, and fine tuning is performed at the TMC by traffic engineers to verify operation and optimization performance. The County’s ASCT has been found to provide significant improvements to traffic flow on the pilot corridor.