| The objective of this study was to determine the merits of alternative signal control strategies and to quantify the magnitude of the incremental benefits that might be achieved through changing the control of traffic signals in urban corridors from fixed-time or actuated control to more advanced computer-based adaptive control systems. Two adaptive signal control strategies, with two different techniques for traffic profile predictions, were examined in the study. The analysis was conducted using simulation modeling of a hypothetical corridor with traffic profiles representing moderate and high peak-hour conditions. A real-time adaptive control algorithm was incorporated with the CORSIM simulation model. The algorithm provided real-time adaptive control for the traffic signals along the corridor based on detector data exchanged with the simulation model.; The effectiveness of different signal control strategies was examined using the same platform. The output of the simulation model showed that adaptive control strategies resulted in a reduction in average intersection delay and corridor travel time over optimized fixed-time signals. The reduction was higher during the non-peak periods and decreased as traffic demand reached its peak with average saving in total travel time ranging from 1.89% to 5.90%. When compared with the coordinated actuated signals, neither of the two adaptive control strategies showed a significant difference in corridor travel time or intersection delay parameters. The saving in corridor travel time under adaptive signal control system is more sensitive to the PHF of the minor-street traffic than any other traffic parameter. There was no significant difference in the performance of the two adaptive control systems that used different traffic-profile prediction techniques.; A field study to examine the effectiveness of deploying the SCATS adaptive control system in the Orchard Lake Road corridor showed that the reduction in corridor travel time achieved under SCATS control was within the benefit limits predicted by the simulation model. The results also showed that, similar to what the simulation model output demonstrated, coordinated actuated signals might have achieved a similar reduction in travel time.; This research has contributed to the understanding of the potential benefits of adaptive signal control strategies in urban corridors. It also identifies several areas where there is a need for further research that can, ultimately, lead to a set of rules and guidelines for choosing among different signal control strategies within an ITS context. |
