Research On Setting Of Mid-block U-turn Opening On Urban Arterial Roads

With the development of the city,the high intensity of land development and use along the road,and traffic management means innovation,the number of U-turn bays are raising on the arterial roads.As lacking relevant standards,the setting of them usually with arbitrary,which not only affects their function but also bring a lot of negative impact to road traffic.This paper make research on optimize setting of U-turn bay,to make them become the arterial roads’ "friendly" facilities rather than the traffic "interference" risks.This article first analysis the features and the the traffic characteristic of U-turn rotation,investigate the traffic impact mechanism of mid-block U-turn and the main factors and subjects were defined.The positional relationship model between U-turn bay with intersection,entrances and exits,bus station,the three main subjects were established respectively.Base of it,with the goal of demand optimization and traffic impact minimization,a comprehensive location model of U-turn opening was set up.In addition,the VISSIM simulation was introduced to deal with the problems of the limitation of theoretical model itself and modify the model,making the preferred scheme more practical significant.Then,from the perspective of regional to analysis the regional transport effect brought by U-turn opening and optimize regional signal,and the “four phase" Setting method for mid-block U-turn opening was put forward.Next,a "comprehensive" U-turn ports setting on one of Wuhan arterial road set as an example to makes an empirical analysis on theory and method proposed in this paper.The case study demonstrates: 1)there is a certain gap between the optimal scheme selected by the method of this article and the theoretical method,but within the effective range,which on one hand verify the validity of the model,but also shows the only theoretical calculation is likely to get the optimal results.2)U-turn median opening location can improve traffic situation and meet the diversified demand,making the arterial road’s traffic function and service function were be well realized.3)But at the same time,it brought some negative impact,mainly lies in: part of the traffic pressure was transfer,average speed was reduced and the speed dispersion increases.4)By the optimal design of signal timing scheme of the affect region,can effectively improve the overall regional transportation operation.Finally,some issues for median U-turn applied on urban arterial were put forward combining with this research and main problems of current situation,being of a help for the application of median U-turn on urban arterial.