Due to the short spacing, mixed traffic flow conflict, unreasonable signal control and other reasons, the urban close intersection group is easy to cause the intersection conflict, vehicle queue overflow and intersection control delay accumulation. The coordinated control strategy optimization of close intersection group is an effective measure to improve the traffic capacity and operation efficiency of intersection group. This paper discusses the traffic flow characteristics of close intersection group and the influencing factors of traffic capacity. Combined with the design method of intersection traffic signal coordination control, by increasing the pedestrian crossing time, an optimization method of average crossing time between intersections based on the output of simulation platform as the phase difference is proposed, which enhances the compliance of the reality. The typical close intersection combination in Zhengzhou is selected as a case study. Based on the original signal timing scheme, the timing extension strategy and the timing shortening strategy are proposed, and the effectiveness of the optimization strategy is tested by VISSIM simulation platform. The results show that under the same traffic volume, the timing extension strategy and timing shortening strategy are significantly improved compared with the original control scheme. The average vehicle delay decreases by 18 % and 21 % respectively, and the queue length decreases by 16.7 % and 19 % respectively. This shows that the implementation of the signal coordination control strategy of the urban close intersection group can effectively reduce the vehicle travel delay and queue length, which is helpful to further improve the traffic efficiency of the urban close intersection group.
 

traffic control, close intersection, traffic simulation, signal control strategy, capacity