Four-factor Index Based Road Network Planning Method

Road transportation is an important condition for socioeconomic development, and a significant foundation for integrated transportation. Since the reform, road transportation has progressed rapidly, and its constraint on socioeconomic development has been relived a lot, but the contradictions of quantitative insufficiency and structural imbalance still exist. At the same time, transportation demand is significantly changing and environmental resources are increasingly tense, which challenge the further development of road transportation. Under such circumstances, the further development of road transportation should be demand oriented development, take the maximization of socioeconomic contribution as a goal, to meet the demands and save the costs maximally, and realize the best match of demand and supply.Take the regional road network layout as study object. Considering the industrial property of road transportation, analyze the different decision goals of mainly related stakeholders and their relationships from the perspective of value flow, and then select the four factors of construction cost, land opportunity cost, transportation cos t and road network efficiency as decision variables to build up road network four- factor index. And on the basis of this, study the layout method of road network to meet the transportation demand maximally. Firstly, divide road network layout into distributed type and centralized type according to the distribution of road infrastructure, and analyze the influence of nodes location and demand distribution on four- factor index of the two layout types, which determines the basic pattern of regional road network. Secondly, use attracting scope model and OD projection model to simulate the attraction of traffic lines, and the method of demand axis identification is developed by OD clustering analysis, which figures the focus of regional road network planning. And finally, according to the theory of road function classification and node hierarchy division, develop the layout methods of arterials, collectors and local roads respectively, after that, aim at the optimization of basic structures, propose an optimizatio n model by adding virtual node, and use particle swarm optimization algorithm to get the numerical solution, and then obtain the final network layout.The road network planning method takes transportation demand as the leading goal, to realize the best match of demand and supply, which is good for greatest satisfaction of transportation demand and efficient allocation of transportation resources. In the process of modern integrated transportation, the increment construction and stock optimization should coordinate with each other, make full use of the increment advantage and stock potential, and promote the optimization of stock by construction of increment, in such way, realize the global optimization of road network.