Performance Measures of Manual Multimodal Traffic Signal Control

Abstract

Representatives of traffic control agencies (TCAs)—including police officers, firefighters, and other traffic law enforcement officers who override automatic traffic signal controls—are crucial to the mitigation of nonrecurrent traffic congestion caused by planned and unplanned events. An unanswered question is how well TCA officers perform compared with state-of-practice automatic traffic signal controls. This study assessed the performance of TCA manual multimodal traffic signal control during special events. First, an interview was designed to promote understanding of the control rules of TCAs and the practice of manual traffic signal control. Next, a simulation experiment was conducted to record control actions during multimodal traffic flows containing buses, pedestrians, and passenger cars. Third, a TCA performance index was developed through a comparison of manual control with actuated signal control and optimal control solutions from an online optimization model, which assumed the availability of rich vehicle information, to determine the best control strategies. The results show that manual traffic control can significantly improve control performance, even to the point of approaching the performance of the optimized timing plan. Large variations, however, were observed during the study.