A Relaxation-Enabled Band Model for Network Traffic Signal Optimization

Network traffic signal optimization makes the entire traffic condition of a city more efficient. This paper presents a relaxation-enabled band model designed to optimize the green wave of each arterial and coordinate two intersecting green-wave arterials. Because of the existence of outer loops, the feasible region of a traditional model may be narrow or even empty. To solve the problem, the proposed method permits the green wave of some road sections to be broken and optimize the signal coordination. The relaxation-enabled band model is formulated as a mixed-integer linear program, which can be solved by the branch and bound algorithm. A network instance has demonstrated that the relaxation-enabled band model can relax the feasible region and obtain the optimal solution of area signal optimization while the tradition model has no feasible solution. The proposed model is more suitable for coordinating signal timing in complex network environments than the existing model.