Research On Design Method Of U-turn Traffic At Entrance Of Urban Road Intersection

There is a demand for vehicles to U-turn at urban road intersections.The design method of the U-turns under different traffic conditions are different.At present,there is a lack of systematic research on the design method of the U-turn traffic at the entrance of the intersection,and the relevant theoretical research results have not yet been formed.In the actual engineering design process,designers often rely on experience to qualitatively design the U-turn traffic,lacking quantitative basis.The U-turn flow of the urban road intersection with the left-turn dedicated lane and the left-turn dedicated phase is treated as the research object.By analyzing the operation characteristics of U-turn and the influences of different design modes on other traffic flows in the intersection,the U-turn design method are studied.The main research contents are as follows:(1)In order to determine the optimal U-turn design mode under different roads and traffic conditions,the influences of different U-turn design modes on other traffic flows in the intersection is analyzed.The occupants in the vehicles and the pedestrians in the direction are treated as a whole object,and the per capita delay calculation model is established.Finally,the U-turn design mode selection model is established with the goal of the lowest per capita delay.(2)To determine the suitable conditions for the U-turn traffic,so that the vehicles can pass safely and orderly,the running trajectories characteristics of the U-turn vehicles are analyzed and the U-turn space calculation discriminant model is established.According to the vehicle queuing theory and the lane change theory,set position calculation model for setting the U-turn opening upstream of the guide lane is established.(3)To determine the appropriate median opening width for U-turn,a median opening width calculation model is established considering driver behavior.At last,the design method for U-turn of the urban road intersection with the left-turn dedicated lane and the left-turn dedicated phase is proposed.The recommended values for the median opening width under common road conditions are recommended.The U-turn traffic design method for urban road intersections from the perspective of system optimization is proposed,which can provide scientific and effective design basis for engineering designers and provide scientific traffic management decision-making basis for traffic managers.