Secondary Coordination at Closely Spaced Actuated Traffic Signals

This paper presents a method of addressing stochastic variation at closely spaced signalized intersections to provide secondary coordination to “minor” movements with significant traffic volumes. A neurofuzzy signal control system was designed in this study to manage a noncoordinated movement to avoid queue spillback. Building on the conventional actuated-coordinated control system, the neurofuzzy controller does not lose the benefit of the primary coordination of the conventional controller but establishes a “secondary coordination” between the upstream coordinated phase (through phase) and the downstream noncoordinated phase (left-turn phase) on the basis of a real-time traffic demand. Under the neurofuzzy signal control, the traffic from the upstream intersection can arrive and join the queue at the downstream left-turn lane and be served in a timely fashion and thus reduce the likelihood of being delayed at the downstream intersection. The simulation results indicate that the neurofuzzy signal control consistently outperformed the conventional actuated-coordinated controller in terms of reduction in systemwide average delay and number of stops per vehicle under a wide range of traffic volumes by nearly 20% under heavier demand conditions.