Global Adaptive and Local Scheduling Control for Smart Isolated Intersection Based on Real-Time Phase Saturability

Abstract

Linking real-time phase saturability directly to the traffic signal control, the global adaptive control scheme for traffic light loop and the local scheduling control strategy for phase green time are proposed in this paper for real-time traffic signal control systems with multiple phases. First, applying the real-time phase saturability of each phase as the time-varying weight factor, an elastic scheduling model is designed to describe the competitive relationship among the different phase in a traffic light loop. Then the traffic green time scheduling problem in a traffic light loop is formulated as a trade-off optimization problem between the green light time and real-time phase saturability for each phase. By solving a quadratic programming problem that seeks the minimum value of the sum of the squared deviation between the green time and the maximum allowable green time in each phase, the allocated green time in next traffic loop is obtained. If the total real-time traffic load exceeds the allocable maximum value or unreaches the allocable minimum value, the proportional global adaptive control schemes are triggered for rearranging traffic light loop time. Undertaking different traffic flow conditions, the effectiveness of proposed adaptive control schemes and scheduling strategies are illustrated compared with the classic average allocating method.