Study On Optimization Of Highway Networks Layout Based On Urban Agglomerations

As the development of the scale of highway construction,the planning of highway networks have been paid much attension by highway administration aggency, and the theorey and the methods of optimum distribution has become the hotpoints issue for the highway researchers. As a classical traffic planning theory, the four-stage method has been widely used, But it has shown the limitations to solve traffic planning theory on base of urban agglomerations. Now the study on highway network layout optimization based on urban agglomerations is a new problem facing us. So in this paper , it is mainly concerned with the study of highway network layout optimization of urban agglomerations based on traffic integration, and the deeper study on planning theory of highway networks. This research was presented insix main categories:(1) Research had comprehensive description on study on optimization of highway networks layoutbased on urban agglomerations .In the first part of this paper, the basic concept about the urban agglomerations and traffic integration are discussed, the main type, action and development of urban agglomerations at home and abroad are introduced. On this base, the difference of urban agglomerations between abroad and home are given, and establishment of the system of traffic integration are also discussed.(2) The node hierarchy division methods are summarized and analyzed in this paper. Through considering nodes' transportation level, this paper will nodes' traffic as an index ensuring of degree of importance of node, and improved the existing degree of importance model of node. And highlight introduced two new thinking methods of cluster analysis.(3) For the current situation of urban agglomerations transport development, studied Combination traffic demand forecasting methods that suitable urban agglomerations. designed a combination forecasting process, rule out the possibility of combination forecasting model, the possibility of the existence of redundant methods. And the central urban agglomerations of Liaoning province as an example of the use of the method.(4) The layout methods of region highway networks were discussed, and by comparing adavantages and disadvantage of different layout methods, the new method applying for urban agglomerations was put forward. This methods stressed on degree of importance for combined layout of regional location. In the last part, some factors were given for solving highway network layout optimization of urban agglomerations based on traffic integration.(5) On the base of works abovt, the combination optimization model,which is suitable to solve the layout problem of freeway and first-grade highway, was established using the combination optimization theory, and the bi-level planning model was established,which is suitable to solve the second-grade highway. applying respectively linearity weighing and summing method and multiply-divide method, the highway network layout combined optimization model and bi-level planning model are converted into single objective optimization model. The paper developed random happening value algorithm host program to solve urban agglomerations highway network layout optimization problem by VB language.(6) The planning problem of the middle part cites group in Liaoning province was anaylied using the the combination optimization model and the bi-level planning model, that has proved effectiveness and reasonability of the model.Finally, the paper made a conclusion on research, and also presented further orientation of future research.