Study On Traffic Flow Characteristics And Capacity In Bottleneck Sections

At present, due to the inherent physical line, road construction, the ramp impo rt, bad "slow" driving behavior and so on, each sector of the urban road cause t raffic bottleneck. The traffic bottleneck will have a negative impact on urban traf fie. The traffic bottlenecks often features simple but have complex traffic situatio n. A driver’s behavior choice and lane changing will have great influence on tra ffic bottleneck capacity. In this paper, on the basis of traffic capacity calculation f or free and mandatory lane changing, taking the microscopic simulation model of the measured data of calibration parameters as a tool, to research the selection o f driver’s driving behavior on the bottleneck link and the effect of the static and dynamic bottleneck on urban traffic.Firstly, by dividing the bottleneck of lane changing form, distinguish the two for ms of free lane change and mandatory lane change through the main lines spacing. TheoretLcally analysis the effect of two kinds of change on the main traffic flow, that is to obtain the function on the basis of the free lane change number which can be accommodated and be inserted into the gap and free change distance, the function based on the main ideal of mandatory lane changing of speed - density f unction. The two change forms determine the capacity of the bottleneck link toget her, on the basis of these two functions, to obtain the function of static bottlenec k’s ideal capacity on account of the assumptions of the fixed lane change distan ce.Secondly, this paper puts forward the calculation method based on the bottlenec k link in weaving area, and analyzes the difference and relation between bottlenec k weaving area and expressway weaving area. From the point of view of free la ne change distance, to analyze of the influence of bottleneck weaving area on th e capacity of bottleneck link, then to obtain the function with independent variabl e of the bottleneck link’s capacity and the distance of bottleneck weaving area.Again, on the basis of the ideal capacity function of static bottleneck, it establis hes the relative coordinate system to turn the dynamic bottleneck formed by slow cars into a relatively static bottleneck, and analyses the traffic flow parameters of the relative coordinate system, then to establish the ideal capacity function of the dynamic bottleneck under the relative coordinate system.Through the analysis and comparison of the existing micro simulation software a nd its core model, to select the traffic simulation software suiting for the bottleneck link, to calibrate the parameters of traffic flow based on practical data. On the b asis of traffic flow with calibrated parameters, to simulate and compare all the fu nctions in this paper, then to verify the reliability of the function.