Types Of Urban Interchange Selection Based On Multi Factors Influence

The Urban interchange has been widely used as an important measure to solve the problem of urban intersection in many cities, especially in big cities. The type selection of interchange is the most important link in both pre-construction and design of interchange, and its basis is to establish a system which is used for its classification and coding. Fundamentally speaking, the type selection of interchange is a multiple attribute decision making problem as it is affected by many different factors. Existing selection methods of urban interchanges are that transportation engineers select a series of possible interchange proposals based on their work experience, and then calculate the traffic capacity of possible prosposals’and compare them to determine the last proposal. But in fact, the effect of urban interchanges is not very good because the common classification methods of interchange are too rough, and the selection options are largely dependent on engineers’personal experience and their ability which are lack of necessary theoretical basis, and the factors which influencing urban interchange type’s selection are usually not considered fully. To solve the above problem, this paper systematically studies the classification system of urban interchange and the factors which influencing urban interchange type’s selection, and then establishes a set of urban interchange selecting method theory.Firstly, on the basis of analyzing traditional urban interchange classification system, types of urban interchange is redefined and the interchange classification system is established according to exits and entrances of the left turning ramp as well as whether existing small ring roads and weaving section of ramps. After confirming the types of interchange, the author adopts binary coding method to encode for different overpass types. Different interchange forms and coding are illustrated and we find the adopted coded way is easy and simple.Secondly, based on the analysis of the factors, influencing urban interchange type’s selection, and their impact mechanism, a quantitative description for the quantifiable factors, such as capacity, the effects of network is given. Change Rules between other unquantifiable factors and urban interchange are found.On this basis, a Bi-level Programming model is built which consider of quantifiable factors. Taking into the important impact of the node of road network on Bi-level Programming model, the node steering delay of road network is brought into the model. The upper level model is objective to the minimum of impedance which includes steering delay and can be solved by the combing Algorithms of Scatter Search Algorithms and Improved Adaptive Genetic Algorithm. The lower level model is a traffic distribution problem under Stochastic User Equilibrium Model which includes steering delay and can be solved by the Method of Successive Averages. The selection options of urban interchange are obtained by solving the Bi-level Programming Model. And then, a Multiple Attribute Decision Making theory method is used by’taking the influence factors which cannot be quantified as decision-making index. At last, the models will be solved by Visual C++software.