Study On Traffic Flow Characteristics And Control Technology Of The 3rd Ring Expressway Entrance In Fuzhou City

The rapid development of economy and society make people's living standards improved,and the amount of vehicle increased year by year.However,the construction speed of transportation infrastructure is behind the speed of travel demand growth rate,which causes the urban traffic congestion problems.Another Traffic controlling faces the embarrassing situation which is stop-gap measures.The entrances are the traffic bottleneck which link the 3rd ring expressway in Fuzhou city and other road,and the entrances are the important areas of urban traffic congestion.The traffic conditions of these region play a serious impact on the traffic efficiency of the 3rd ring expressway in Fuzhou city.So it is necessary to study the traffic flow characteristics of the 3rd ring expressway entrance in Fuzhou city,and apply reasonable and practical traffic management and control technology to solve the urban traffic congestion problem.Firstly,this paper sums up the research results of the expressway traffic flow characteristics and control technology at home and abroad,and analyzes its main research methods.This paper analyze qualitatively the operating characteristics of the imported vehicles which are in the entrances by traffic wave theory.Moreover,this paper explains the principle,using conditions and main methods about ramp control of the urban expressway entrance.Secondly,according to entrance regional of research needs,this paper determine the research method.The UAV is used to obtain a lot of traffic flow data under the guidance of the research method for data acquisition.Based on the measured traffic flow data of the 3rd ring expressway entrance area in Fuzhou city,the writer analysis and draws the time-varying characteristics figures of three traffic flow parameters in the different lane of each observation area and vehicle lane-changing trajectory figures of entrance ramp.From the perspective of the lane,the writer analysis the time-varying characteristics of traffic flow parameters in every areas of two different types of entrance.Moreover,the writer analysis the vehicle lane-changing trajectory characteristics of entrance ramp.Research findings show that,the inner and middle lane present similar variation in flow and density,but its flow and density distribution is always greater than the outside lane.The speed changes of the outer lane in volatility is larger than the inner and middle lane.Traffic flow basic parameters of three areas have apparent oscillation characteristics and its change regulation present certain similarity in weaving and downstream area.The influence of traffic flow of the entrance ramp imported the main road on each lane in the order of the outer,middle and inner lane.Finally,this paper put forward entrance control technology from the angle of traffic conflict and access management,which adopts the isolation guardrail between the acceleration lane and the outside lane for trafficcontrol in the 3rd ring expressway entrance in Fuzhou city.What's more,this paper use VISSIM software on entrance control technology for traffic simulation and validate entrance control technology of practical and effectiveness by quantitative comparing the control effect of using the control technology before and after.The simulation results show that the entrance of the type of the ground auxiliary road should appropriately use 50 meters long isolation guardrail,which can shorten the travel time by 13.41%.And the entrance of the type of the interchange ramp should appropriately use 45 meters long isolation guardrail,which can shorten the travel time by 13.41%.