Quantifying Delay Reduction to Buses with Signal Priority Treatment in Mixed-Mode Operation

The benefits of the signal priority system to buses in terms of delay reduction in mixed-mode operation have been quantitatively assessed. Analytical expressions were derived to quantify the benefits. Delay reduction under a signal priority system is bounded by signal delay but independent of queuing delay; delay reduction has a high variance/mean ratio, which suggests that sufficient slack time should be built into a bus schedule to maintain reliable service, even for buses that receive priority treatment; the benefits are more significant for buses traveling on cross streets than for those on main streets because the red phase for the cross street typically is much longer than the minimum red required for pedestrian crossing.