Theory Of Road Network Planning And Evaluating In Metropolitan Area

Metropolitan area is the inevitable stage for city, and it is the important embodiment of competitiveness for a country or region. Road system is an important carrier for all material and objects flowed in metropolitan area, which leads the economy and society of the region to a continuous, fast and harmonious development.In order to meet with the traffic demand in the metropolitan area effectively, and to avoid the waste of construction sources and road facilities, it is required to establish scientific and systematic road network planning. With the development of the social economy and communications and transportation, Traffic demand on road network system improves constantly. Meanwhile, a lot of problems concerning to road planning and construction in the past appears, so it is especially urgent to study road network planning theory deeply. Road network optimization theory and evaluation method were studied in the dissertation on the basis of optimization theory and modern combination optimization theory, thought of systematic engineering, existed findings about road network optimization, systems analysis, qualitative analysis and quantitative analysis, and so on.Firstly, basic theory of the metropolitan area was introduced in the dissertation, and an improved gravitation and field intensity model was used to process demonstration research on definition of Beijing metropolitan area scope. From the actual condition of Beijing and the thought of "Diffusion" and "Re-concentration", a whole development idea of round and multi-functional intensive structure for Beijing metropolitan area was put forward.Secondly, trend of road network system of metropolitan area was analyzed and forecasted. A location quotient model was used to analyze the tendency of the location quotient of each cities and its passenger transportation and freight transportation, an Equal-length and Changeable-dimension Fractal Model was set up to predict the development tendency of road passengers and goods traffic structure, and an entropy change model was established to analyze the evolution direction of road network system of Beijing metropolitan area based on entropy theory.Thirdly, on the basis of the "four-step" method for traffic demand forecasting, and according to the characters of intercity traffic in metropolitan area, three indices, including economy, rapidity and convenience, were used to set up a new logit model suitable to modal split of passenger traffic, and method for calibrating the parameters of the model was introduced. Next, Beijing metropolitan was taken as an example to carry through the demonstrative study of traffic demand forecasting.Fourthly, according to the actual needs of the road network optimization, a two-stage bi-level programming model was presented in the dissertation on the basis of existed research of network design, including long-term optimization model and short-term optimization model. And Genetic Algorithm was used to solve the bi-level models, and the road network optimization of Beijing metropolitan area was taken as an example.Finally, theories of DEA and weighted gray correlation analysis were combined to evaluate the comprehensive level of road network system in metropolitan area. The new method can avoid the subjectivity when the weight vector is determined and get the optimality of the prior order evaluation by non-uniform weight.The following are the main conclusions of this dissertation:(1) A model of gravity and field strength was improved, and a comprehensive development strategy of "round and multi-functional intensive structure" was presented.(2) A new fractal forecasting model was put forward-"Equal-length and Changeable-dimension Fractal Model Using Compensating Figure", and an entropy change model was build to analyze the developing tendency of road system.(3) Using automobile, long-distance bus and railway as objects, a new logit model was presented, which is more suitable to modal spit in metropolitan area.(4) A two-stage and bi-level programming model for mixed transportation network design problem was presented which is composed of long-term model and short-term model. And the Genetic Algorithm is used to solve the model.(5) A new model called weighted gray correlation analysis method based on DEA (Data Envelopment Analysis) was presented to evaluate road network system in metropolitan area.