Traffic signal perimeter control with multiple boundaries for large urban networks

A new gating strategy based on the notion of the macroscopic or network fundamental diagram (MFD or NFD) and the feedback-based gating concept is introduced and tested successfully. Different regions of large-scale urban networks may experience congestion at different times during the peak period. In this paper, the zone including the initial core of congestion is considered as the first region which has to be protected from congestion via gating; eventually, as the congestion continues to expand, the border of an extended network part becomes the second perimeter for gating control. Extensions while distributing the ordered controller flow to the gated traffic signals in case of low demand or occurrence of spillback are also introduced. A greater part of the San Francisco urban network is used as test-bed within a microscopic simulation environment. Significant improvements in terms of average travel time and average delay are obtained compared to the single perimeter gating and non-gating cases.