Research On The Calculation Method Of Traffic Delay And Optimal Control Strategy At The Crosswalk

Mixed traffic flow and complex travel modes are the main features of the urban traffic flow in China. Especially in typical traffic bottlenecks, the interactions of different traffic participants make the traffic congestion more serious, and thus increase the risk of accidents. Traffic delay, as an important measurement to evaluate the level of service of the bottleneck, has become the focus of many researchers. However, most of these studies concern only on the single traffic participant, and the interactions among different participants are ignored. Furthermore, research on traffic delay of mixed traffic is still at an initial stage, and most of these models are based on micro simulation approach. Therefore, there is really a need to study the delay of mixed traffic both for the development of theory and for practical application in China.This paper mainly works as follows:Firstly, a vehicle delay model influenced by pedestrians was proposed. The vehicle delay was divided into two parts:the delay caused by the signal control and the delay caused by pedestrian breaking the red light. And then based on shockwave theory, this paper develops an analytical model of vehicle delay at signalized crosswalk. It was found that the feasibility and accuracy of the proposed model all outperform the results form VISSIM simulation. In addition, we analyze the characteristics of vehicle delay.Secondly, a pedestrian delay model influenced by vehicles was developed according to different behaviors of pedestrian when crossing the crosswalk, either following the rules or breaking the rules. By introducing the rate of breaking the red light for pedestrian, an analytical model for pedestrian delay at signalized crosswalk, which is derived from the truncated Adams model, was developed to investigate the influence of vehicle flow and other factors on the pedestrian delay.At last, an optimal model of signal timing control system was presented. The vehicle and pedestrian delay model for mixed traffic environment are applied to the optimal control strategy at a signalized crosswalk. By setting derived from the truncated Adams model minimum average vehicle and minimum pedestrian delay as the fixed targets and the maximum capacity the selectivity target, we established an optimization model for multi-stages signal timing control. Taking an actual signalized crosswalk in Beijing as example, this paper optimized its signal control, and analyzed the optimized results under two different optimal models.