Analysis Of Traffic Flow Characteristics In Multi-Lane Weaving Section Of Urban Expressway

With the acceleration of the national economy and social development,the process of urbanization in China is gradually entering a new stage,and urban transportation development begins to face new challenges.At present,the unbalanced development of the demand and supply of urban transportation in China has caused the problem of traffic congestion to be particularly prominent,resulting in a significant reduction in residents' travel efficiency and the efficiency of urban resource transportation.Excellent urban expressway system is the key to improving the internal transportation efficiency.However,the urban expressway system in China is still at the stage of construction,and the knowledge of impact on the operational characteristics in the weaving sections is still insufficient.Therefore,in order to alleviate the increasingly severe congestion of weaving section in urban expressway,considering the impact of temporary out of vehicles,this paper combines the factors such as safety lane changing distance and lane changing decision-making.A multi-lane waving sections discrete model based on cellular automata is established,aiming at providing a scientific reference for the optimization of urban expressway waving sections.Firstly,this paper combines China`s special traffic environment and then makes a comparative analysis of the characteristics on the urban expressway waving sections.This paper studies the impact of the waving sections structure type,the waving sections length,the number of the waving sections,flow ratio of the waving sections,ration of the waving sections and weaving area speed indicators,and then establish vehicle lane change behavior benefit evaluation system,basing on the driver's decision-making process of lane changing in waving sections,in order to make the lane changing behavior of the model more reasonable.At the stage of analyzing the characteristics of vehicles in the waving sections,this paper considers the impact of factors such as the operational characteristics,changing lane behavior and the destination.The results show that traffic flow of the waving sections will cause a great disturbance.According to different choices of departure lanes for departing vehicles,they are divided into regular exit vehicles and temporary exit vehicles,and their characteristics of driving speed are analyzed.A safe lane changing distance calculation model based on the vehicle speed is established.Finally,by analyzing the operational characteristics of the vehicles in the waving sections,this paper uses the theory of cellular automata to establish multiple lanes waving sections model of urban expressway,and simulate the evolution of the traffic flow of various conditions,analyzing the evolution of the waving sections.Results show that the model of multiple lanes waving sections can reproduce more reasonable traffic flow situation in waving sections,the conventional exit vehicles and temporary exit vehicles have great significance on traffic flow of the waving sections.Temporary exit vehicles cause a severe disturbance in the waving sections.The length of the waving sections will affect the road capacity.In addition,the bottleneck phenomenon in the urban expressway interweaving sections is mainly caused by intertwined traffic flow,so this paper takes the characteristics of exit vehicles and temporary exit vehicles into account,and separates weaving vehicles and main road craspedodrome,temporarily guiding the exit vehicles changing lane ahead of time,only in this way can effectively alleviate the traffic congestion of urban expressway waving sections.