Evaluation of Manual Traffic-Signal Control under Oversaturated Conditions Using Hardware-in-the-Loop Simulation

This paper quantitatively assesses the performance of manual traffic-signal control by comparing its performance with two optimized traffic-signal controls during oversaturated conditions. To simulate manual traffic-signal control, the VisSim-based hardware-in-the-loop simulation (HILS), which provides similar manual controls at a field traffic-signal, was implemented. Whereas the normal-day traffic signal-timing plan was obtained from the city of Charlottesville, optimized signal-timing plans were obtained from Synchro. The results obtained from the VisSim-based simulation indicate that benefits can be achieved by utilizing manual traffic-signal control and optimized signal-controls relative to normal-day traffic-signal control during oversaturated conditions. In particular, manual traffic-signal control reduced delays to a greater extent than the two optimized signal-timing plans. Although the reduction in delays achieved by the manual signal-controls was not statistically significant when compared with the performance of the two optimized signal-controls, the results of the third and fourth manual signal-control attempts by the same operators reflecting the performance of trained manual controls showed statistically significant improvements in reducing delays.