Research On Optimization Theory And Method Of Urban Road Ransportation System Based On Traffic Efficiency

The traditional construction and management of urban transportation is often passively adapted to the growth of total traffic demand. Because of the lack of system considering urban form, population scale, level of economics development, land-use distribution, rational allocation of resources, relationship between environmental protection and urban transportation system, and ignoring the balance of traffic demand and supply, all of these factors resulted in low traffic efficiency, lack of order of the traffic demand and the effectiveness of traffic supply.In the new process of urban transport planning and traffic management, if we take the maximization of urban traffic efficiency as the goal of urban transportation system optimization, and the total impedance, the energy consumption and pollutant emissions are all considered as objectives, that the dynamic relationship of urban transportation system and the distribution of land-use, the resource consumption, the environment protection, can be reflected to meet the objective of maximization of social and economics benefits.Based on these, in accordance with the sustainable development ideas of urban transport system, starting from the relationship between supply and demands of urban road transportation system, the optimization problems of urban land-use patterns, the allocation of urban road network and urban traffic structure were analyzed. Then the optimization theory and methods of urban road traffic system based on traffic efficiency were established in the dissertation, which exploring the establishment of the people-oriented, efficient operation, the harmonious development of urban transportation system, including a number of properties. Thus the innovation of the new ideas and methods in urban transport planning and management were produced, the study can eventually alleviate or completely solve the problem of urban traffic congestion, air pollution and energy saving etc.The main contents are as follows:Firstly, based on a large number of summaries of reference, we analyzed the causes of modern urban transport problems, and reviewed the current domestic and foreign urban transport system, urban traffic efficiency, the relation of urban traffic structure and land-use form. The major factors of urban traffic efficiency are pointed out, including:land-use form, road network layout and traffic structure.Secondly, the structure and features of urban road traffic system are analyzed in this dissertation, and the basic theories of classification, composition, characteristics and allocation levels of urban road traffic resources were put forward. In addition, the forecast of urban transport amount and road traffic supply were discussed. Then the definition and measurement of traffic efficiency were proposed, which provide the means and methods to optimize urban road transportation system.Thirdly, we built the optimization models of the multi-center&group-layout urban land-use form, and proposed the genetic simulated annealing algorithm to solve the models. In this dissertation, the total time of road traffic consumption, pollutant emissions and energy consumption were taken as measuring indexes of traffic efficiency of multi-center&group-layout urban road traffic system. And the generalized cost is the objective function value, with the introduction of economic conversion factor. Based on this, the road traffic pollutant emissions and energy consumption are taken as the one of the goals in the optimization models, in order to develop the improved land-use form optimization models, and the corresponding algorithm and example analysis were put forward.Fourthly, base on the analysis of traditional urban road network optimization models, we pointed out the limitations of these existing models and methods, and introduced typical Bi-level programming models of urban road network. Then the optimization methods and Bi-level programming models were put forward based on the objective of traffic efficiency maximization. This optimization method can meet the different levels of green transportation travel demand, but also to achieve other goals, such as improving urban land-use, resource conservation, environmental protection and urban living environment. All of these reflected the sustainable development of urban road traffic planning ideas, and provided a new way of thinking and methods to solve the problems of irrational urban traffic structure and urban traffic congestion.Fifth, after studying the shortcomings of traditional urban traffic structure optimization, we took the traffic pollution costs and energy consumption costs into the objective function of optimization models. Considering the major impact factors of urban transport trips, we built the road integrated impedance function and the optimization models of urban road traffic structure based on traffic efficiency, in accordance with the mixed road traffic characteristics and the principle of stochastic user equilibrium.