Coordinated control of urban expressway integrating adjacent signalized intersections based on pinning synchronization of complex networks

Abstract

The aim of this work is to investigate the coordinated control of urban expressway integrating adjacent signalized intersections based on pinning synchronization of complex networks. An expressway network integrating adjacent signalized intersections was used as the studied object, where no signal light is set on ramps and ramp metering is achieved only through the use of signal lights at adjacent intersections. An improved cell transmission model (CTM) for each segment of the studied object, comprising a mainline, an on-ramp, an off-ramp, side roads, and adjacent intersections, was established. Each node of the system was defined, and a node coupling model integrating adjacent signalized intersections was also established. The coordinated controller was designed, with the signal timings of adjacent intersections used as decision variables. Using the stability theory of complex networks, the concrete pinning nodes corresponding to the subsystems of regulating the inflow from on-ramps adjacent intersections to mainline could be obtained, and the signal timing schemes at intersections could be optimized. The outflow from the mainline to off-ramps adjacent intersections could be appropriately regulated in order to mitigate off-ramp congestion. The proposed method was validated through simulation experiments. The results indicate that the traffic jam phenomenon can be suppressed utmost, off-ramp congestion can be mitigated, and the operational efficiency can be enhanced at minimal control cost.