Impact of Adaptive Traffic Control System Implementation Methods on Operations of a Coordinated Network

Abstract

To mitigate the negative impacts of traffic congestion, researchers developed adaptive traffic control systems (ATCSs) that adjust signal timings based on real-time traffic conditions. Despite significant attention over the past 15 years, it is not clear how beneficial ATCSs are. The major focus has been on ATCS logics. We shift the focus to examines three ATCS implementation methods by using National Transportation Communications for Intelligent Transportation System Protocols (NTCIPs) in fieldlike operations. The first method represents ATCSs that utilize common controller functionalities to extend or shorten phases; the second involves manipulation of detection calls (to control which phase operates and for how long); the third applies an “adaptive” pattern from the controller’s time-of-day database. We aimed to determine whether any of these methods offers distinct advantages over the others. We developed a “simplistic” adaptive traffic control (ATC) logic for calculating adaptive traffic signal parameters. Note that ATC logic serves as the brain that computes these parameters, whereas ATCSs encompass the ATC logic, NTCIPs, and physical connections required to make the system functional. To conduct experiments involving various demand levels, implementation methods, and frequency of applied changes, a microsimulation model of a network in Chattanooga, TN was coupled with SEPAC m60 controllers in a software-in-the-loop simulation. Regardless of method, frequent corrections of offset and cycle length resulted in limited ATCS benefits, as the controller spent most of the time in “transition mode.” This study aims to inform practitioners and decision makers about the most effective methods for implementing ATCSs in the field.