Study On Traffic Organization And Project Evaluation Of Temporary Construction Openings On Urban Expressways

With the increase of urbanization process, there are more and more construction projects around urban expressway, inevitably setting up temporary construction openings on urban expressway becomes more and more. As the main distribution channel for the passenger and freight transport, expressway plays an important role in the urban transportation, it has a large traffic volume and the speed of car is fast. However construction openings increase the exit and entrance of expressway in which vehicles change lanes and adjust speed frequently, it will cause chaos in traffic flow and traffic hazards. Therefore the effect of setting up temporary construction openings on urban expressway can’t be ignored. It’s necessary to take further study.Firstly the paper explores the characteristics of expressway traffic flow from the daily variation and of traffic volume, directional distribution of traffic volume and lanes and speed based on measured data. Then analyze traffic flow characteristics on the road of construction openings from traffic fluctuation, vehicle lane changing and directional distribution of lanes and speed based on the theory of traffic flow.Secondly the paper puts forward principles, process and main content of traffic organization design of construction openings on expressway. This part of content include analyzing the influence factors of located position, comparing characteristics and applicability of three form of construction opening, setting forth speed-change lane in current norms of China, putting forward three-stage speed-change lane combined with probability theory and differential method, explaining the setting of traffic signs marking and safety facilities.At last, the paper evaluates the traffic organization scheme, including Traffic smooth evaluation and safety evaluation. Specifically include achieving the relationship between traffic capacity of the outside lane and the diverging rate of the ramp based on lane theoretical model of the relationship between traffic flow parameters for ramp, establishing mathematical model for the merging traffic volume at urban expressway on-ramp based on the gap acceptance theory, establishing mathematical model for traffic volume of different sections of the outside lane around urban expressway on-ramp based on multivariate regression analysis of testing data on multiple urban expressway on-ramp, establishing capacity model of import-ramp connection segment. Then establishing safety evaluation system and determining the relative weight coefficients of the factors, defining different security levels based on safety index by cumulative frequency analysis, to arrive at the security evaluation criteria.