Study On Optimization Of Traffic Organization During Expressway Expanding Construction

In recent years, expressway expanding construction (EEC) is a hot spot of highway projects in China, it is a major mode to increase highway capacity. Traffic organization is an important work during EEC, which includes many fields such as social and economic development, construction organization and traffic operation organization etc. The effect of traffic organization directly affects the quality and schedule of expanding construction, so traffic organization is a problem not only to difficultly be sloved but also to urgently be solved. The paper has traffic organization during EEC as the object of study and takes system analysis as the method of study to make optimization research. Based on analyzing affecting factors of traffic organization of EEC, the traffic organization is entirely optimized from three levels that are point level (key point of construction), line level (basic section of highway) and surface level (highway network), which aims to make traffic organization plans reasonable, practical and take into account every aspect.The paper regards the point, line and surface of traffic organization of EEC as train of thought, the main content includes as follows:1. Ascertaining affecting factors of traffic organization during EEC; analyzing affecting mechanism of the factors including macroscopic factors, highway network, construction organization plans, traffic volume and traffic capacity; studying different types of construction organization plans under different ways of expanding construction and their advantages & shortcomings; putting forward forecasting methods of short-term traffic volume and real-time traffic volume; inducing calculating methods of traffic capacity under different plans of construction organization.2. Analyzing the roles and key problems of traffic organization of surface level, which is based on layout of highway network; inducing methods of traffic organization such as restricted divergence and flexible divergence, applying Game Theory to analyzing choice behavior of traffic organization methods; based on the model of stochastic user equilibrium traffic assignment with elastic demand and bi-level programming model, establishing restricted divergence model and flexible divergence model to respectively estimate the effect of restricted divergence and flexible divergence, and putting forward the algorithms.3. Analyzing the roles and key problems of traffic organization of line level; ascertaining principles of choosing construction organization plans; putting forward the corresponding plans of traffic organization based on different construction organization plans of section of highway; applying VISSIM to ascertaining the key technical parameters including the effect of large vehicle scale on traffic capacity during EEC, the open length and the standard of speed limit of central isolation belt, the length and the standard of speed limit of basic section of construction.4. Analyzing the roles and key problems of traffic organization of point level; putting forward adaptive filtering algorithm based on the characteristic of periodic change to forecast real-time traffic volume; advancing corresponding plans of traffic organization based on different construction organization plans of bridges, interchanges. expressway service area, tollgates.