Illinois Center for Transportation/Illinois Department of Transportation
Abstract
Field evaluation of adaptive signal control technologies (ASCT) is very important in understanding the system’s contribution to safety and operational efficiency. Data were collected at six intersections along the Neil Street corridor in Champaign, Illinois, before deployment of SynchroGreen, an ASCT system. The volume, delay, and queue length data from the field for the “before” conditions (which is 2013 data) were compared to the data from the first year after implementation conditions (which is 2015 data). The system was installed in early 2015 and fined tuned by the vendor to get the “best” performance. The field volumes were compared for 83 lane groups (approaches). While traffic volume on 48% of the lane groups significantly increased, 48% did not change significantly, and only 4% significantly decreased. The field delays were compared for 83 lane groups; out of which 22% showed significant increase, 64% showed no significant change, and 14% showed significant decrease. Queue length was compared for only 63 lane groups because the remaining 20 lane groups either did not have queue data, or the queue length was insignificant (two cars or less). Out of the 63 lane groups, 32% showed significant increase, but 49% showed no significant change, and 19% showed significant decrease in queue length. ASCT performance was evaluated based on the changes in volume, delay, and queue length combined. An overall performance indicator (PI) was determined as: Imp (Improved), Unch (Unchanged), Det (Deteriorated), or Mix (mixed results). Of the 83 lane groups analyzed, 51% showed improvement, 20% remained unchanged, 28% showed deterioration, and 1% showed a mixed result. The analyses indicated that ASCT made a compromise between the minor and major street performances and, in general, the minor street improvements were correlated with the major street deterioration or unchanged performances.IDOT-R27-127Ope
