Real-Time Timing Of Traffic Signals Based On Time-varying Universe

Most cities of China are facing congestion problems.The intersection is the key point of the urban traffic network,and traffic jams often occur at the intersection.The reasonable setting of traffic signal timing at intersections will promote the urban road transport system to give full play to its functions and improve people's travel efficiency.The urban transport system is a complex and unstable system.Even in a relatively short period of time,the traffic parameters may change greatly.In this paper,the time-varying universe was used,a fuzzy control method based on time-varying universe was proposed to the real-time timing of traffic lights.Firstly,in this paper,the intersection and the four-phase control was taken as the research object.Considering the queuing length of vehicles in each phase direction,the intersection traffic flow conditions were divided into 35 types.Because signal cycles changed with time,the universe of the signal cycle was set to the continuous time-varying universe sequence.The fuzzy cluster analysis method was used to obtain the appropriate signal cycle universe corresponding to the 35 types of traffic flow conditions at intersections.Secondly,under the universe of the signal cycle,the continuous time-varying universe of the traffic time was obtained.The queuing length and stops were used as variables for fuzzy control.The fuzzy control algorithm based on time-varying domain was used to dynamically adjust the length of the green light and the cycle.The timing scheme of traffic lights was obtained.Taking a crossroad in Changsha as an example,the effectiveness of the scheme was verified by VISSIM simulation.The results show that:by adjusting the signal cycle and the length of the green light,the traffic capacity of intersection was enhanced,and vehicle delay time was reduced.Finally,the average delay,average length of queues and stops were used as indicators.The fuzzy comprehensive evaluation method was used to propose a scheme for judging the operational efficiency of intersections.The scheme could evaluate the operational efficiency of the intersection,also could verify the pros and cons of the traffic signal timing scheme at the intersection,and choose a more appropriate timing scheme.