DALI: A Collaborative, Agent-Based Traffic Signal Timing System



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In this dissertation, we present DALI (Distributed, Agent-based traffic LIghts), a smart collaborative traffic signal timing system. With DALI, intersection controller agents communicate with each other through direct links and do not have a supervising unit to oversee coordination. By default, they execute a timing strategy that improves traffic flow. At the same time, they observe and analyze their respective intersections. If, at any given time, an agent determines that its intersection is congested, it deliberates and defines a new timing plan. It also determines which direct intersections may be affected by the new timing plan and communicates with the concerned intersection agents. They in turn communicate with those agents that may be affected, and the process continues until all affected intersections are notified. The agents then negotiate and collaborate with one another to ensure that the traffic flow will be optimized throughout the intersections. DALI was validated by traffic engineers as well as through extensive simulation of the City of Richardson’s traffic network. In addition, hybrid simulations (i.e., integration of controllers in the field with the simulator) were run to verify compliance with the strict traffic regulations. DALI was deployed in a Richardson, Texas, corridor that includes three major intersections. The data collected for a period of three weeks shows that in average, DALI reduced delay by 40.12 percent (43.56 percent during weekday peak hours).



Multiagent systems, Traffic signs and signals, Hybrid computer simulation