A Real-Time Responsive Signal Control System for Commuting Arterials Plagued by Highly-Congested Traffic, Turning-Bay Overflows, and Mutual Queue Blockages

Despite the abundance of literature in coordinated signal controls, effectively contending with excessive delay and lane blockage, caused by either turning-bay overflows or mutual impedance between through and turning queues, remains a critically challenging research issue, especially for commuting arterials experiencing near saturated traffic states and highly asymmetric volume distributions during peak hours. Such mutual queue blockages and resulting excessive delay will inevitably reduce the arterial’s capacity and even trigger gridlocks at its upstream intersections and neighboring networks. To address these issues, this study introduces an Event-based Dynamic Adaptive Signal Control System (E-DASCS), designed to detect, classify, and respond to evolving congestion patterns with customized signal control strategies. In real-time operations, E-DASCS will first monitor the spatial-temporal queue evolution over each intersection and classify the detected queue types as one of the four predefined congestion levels. One or a series of signal plans customized to tackle the identified congestion level will subsequently be selected and activated by the system. Performance evaluation with simulation-based experimental scenarios over a highly congested arterial in Bethesda, Maryland, has demonstrated the promising properties of E-DASCS, compared to non-adaptive systems with the same control objectives. For instance, it has yielded delay reductions of 7.39% and 5.46% per vehicle hour, respectively, in the commuting direction and at the network level, along with an increase in traffic throughput and prevention of potential queue spillbacks. The revealed effectiveness and computing efficiency from extensive experimental results demonstrate the potential for the proposed arterial signal system to be implement in practice.