Evaluation of Adaptive Signal Control Technology - Final Report

Abstract

This report presents the results of field evaluation of an adaptive signal‐control technology (ASCT) system—SynchroGreen— deployed on the Neil Street corridor in Champaign, Illinois. The Illinois Department of Transportation (IDOT) was interested in field evaluation of an ASCT on a corridor, in terms of traffic safety and operational efficiency. SynchroGreen was selected for field implementation on six intersections along Neil Street. This report is the sixth of the ASCT study, and it provides a brief summary of the other studies and new findings regarding the ASCT performance during heavy traffic from the minor street and heavy traffic due to special events. For the “first year” evaluation, data from 2015 was used; and for the “final year” evaluation, data from 2017 was used. Unlike the outcome of the “first year” evaluation, the “final year” evaluation showed improvements on the performance indicator (PI) in only 5% of the lane groups (cases), no change in 32%, and deterioration in 63%. The system was unable to respond properly to volume increases on the minor street (Kirby Avenue), due to either peak‐hour demand or special‐ event traffic, and failed to allocate the unused green time on the major street to the minor street that had cycle failures. Multiple‐vehicle fatal and injury (FI) crashes had a crash‐modification factor (CMF) of 0.67, which was not significant at the 95% confidence level but clearly indicated a decreasing trend due to implementation of the ASCT system. Decreasing trends in the angle and rear‐end crashes, as well as Type A and Type C injuries, were observed; but they were not statistically significant. The travel times were increased in the preferred directions, which was not a desirable outcome. Several recommendations were made to vendors to provide a more desirable ASCT system.IDOT-R27-127Ope