Case Study for Corridor Retiming Using Traffic Signal Performance Measures

Lucy M Richardson, Purdue University

Abstract

Traffic signal timing has traditionally been designed and updated by modeling intersection operations. However, recent technological developments have introduced event logging capability within modern traffic signal controllers, which has shifted the process of retiming from modeling operations to measuring real performance. This allows signal engineers to retime signals on a proactive basis instead of reacting to complaint calls. Various performance measures and applications have been discussed in literature, but there has not yet been a comprehensive study of the process of deploying required infrastructure and conducting corridor retiming using signal performance measures. To develop guidance on deployment and use of signal performance measures for retiming, a case study was performed on State Road 9 (SR-9) in Anderson, Indiana. After completing an inventory of existing equipment on the corridor, traffic signal controllers and communication infrastructure were upgraded to enable the analysis of operations using high-resolution controller data. Using signal performance measures, a synchronized set of time-of-day plans was deployed, which decreased or held constant chronic split failures at most intersections on the corridor and improved travel time reliability. Next, local capacity was modified to improve service to over-utilized side-street and left turn movements, reducing localized split failures from 41.3 to 34.5 split failures per intersection per day. Finally, offsets were optimized to improve progression on the corridor during each time-of-day plan. The average percent of vehicles arriving on green increased or remained constant for all analysis periods, including an increase from 62% to 69% for the southbound PM period, which led to a 1-minute decrease in travel time during this analysis phase. As a result of the upgrade and retiming, travel time and corridor reliability were improved throughout the day, most notably decreasing travel time by 2 minutes from the existing conditions for the southbound PM plan. There were also opportunities to utilize the high-resolution controller data to monitor construction projects on the corridor. This document can serve as a blueprint for an agency or consultant to develop a new timing plan using traffic signal performance measures.

Degree

M.S.C.E.

Advisors

Bullock, Purdue University.

Subject Area

Civil engineering|Transportation

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