A Study On Regional Transport Network Hierarchical Property And Opitmization Design

There are not enough quantitative researches in regional comprehensive transport network reflecting the characteristics of sustainable development such as comprehensive transport network structure and optimal transport network resources allocation. So it is significant in practical engineering and theoretical development to intensively study regional transport network spatio-temporal structure evolution mechanism and laws and application in transport network design and planning.Transport network hierarchy, as a common basic phenomena, whose evolution mechanism and evolutionary relationship with transport network performance are determined by the intertwined interactions of many elements of economy and society, natural environment, and transport system itself. Most existing researches model transport network with a single hierarchy level, separating demand and supply, and ignoring the dynamic interaction mechanism between transport system and regional spatial structure, which result in a defective transport system, with unreasonable distribution and obscure function in all levels, difficult to adapt to regional spatial structure, economic development requirements and changes in traffic demands.From a systematical way, this dessertation research, comprehensively considerates dynamic interactions among several elements, dynamic equilibrium of traffic demand and supply, and coordinates dynamic interaction mechanism and macro-static analysis to formulate transport network evolutionary dynamic system synergisticly dominated by some dynamic rules. Hereafter, evolutionary mechanism of transport network and its hierarchy property are studied, followed by investigation of sustainable multilevel transport network planning and design theory. These researches can enrich and improve the current theories in integrated transport system planning, provide a kind of novel solution approach and development pattern for regional transport network planning with low resource consumption, little pollution, and the ability to effectively enhance manufacture factors convergency and to promote the reasonable distribution of industry and population.The study is mainly reflected in the following aspects.(1) Transport network hierarchy existenceTaking the case of Chang-Zhu-Tan Urban Agglomeration traffic network, network properties are investigated. Investigations and analyses show that the traffic networks have small-world behavior but without scale-free property, and that, among the five traffic networks, the Chang-Zhu-Tan Urban Agglomeration traffic network is strong resilient against failure, and that traffic networks of Changsha and the urban agglomeration are the most orderly systems. More importantly, traffic network hierarchy that received few quantitative proof, has been focused on. The authors are inspired to analyze traffic network hierarchy with disassortativity and to employ the n-degree-n-clustering coefficient relationship to quntitatively characterize hierarchy in the traffic networks. An exciting conclusion is drawn, through numerical results and analyses, that the traffic networks are proved to be hierarchically organized.(2) The evolutionary relationship of transport network performance with hierarchyCombining with traffic produce model, a traffic system optimal model is constructed taking the road users externality into account. The dynamic interaction mechanism between traffic system and regional spatial structure and scale-free network model together with the economic relation concept are invited to design traffic network evolutionary rules. Furthermore, a traffic network evolutionary model and algorithm to disclose the traffic network evolution laws has been established in the guidance of microscopic dynamics and macroscopic mechanism. A case study shows that, during the process of network evolving, hierarchy emerges and turns clearer, and what is more significant is that the total network cost decreases; the computation of a new transport network entropy defined by betweenness centrality illustrates that the network entropy becomes smaller and the traffic network evolves to a more orderly structure with improving performance. The results can provide theoretical groundwork for optimal transport planning.(3) Multilevel multimode comprehensive transport network optimizationGeneralized path cost is formulated with traffic negative externalities and transport network hierarchy involved in. Nonlinear programming is established for Logit-stochastic equilibrium model of multilevel multimode comprehensive transport network. All lead to an algorithm for multilevel multimode transport network design. A series of numerical experiments of example network have been carried out according to the proposed algorithm. Hierarchy elasticity and demand elasticity of nework total generalized cost are defined and focused on; and also the impact of mode split parameter on the total generalized cost of networks with different hierarchical structure and demand elsticity of average generalized cost with different mode split parameter value are analized. Analyses show that the designed comprehensive transport network with transport hierarchy can better adapt to the growth of traffic demands without great network performance deterioration and that hierarchical transport network is relatively insensitive to the change of mode split parameter value.Following foregoing studies, extended studies of multilevel multimode transport network models and algorithms have been carried out under the consideration of elastic demand and link capacity constraints. Firstly, after transport mode split finely defined based on hierarchical property, a multilevel multimode transport network stochastic equilibrium model has been proposed. The equivalent variational inequality of the stochastic equilibrium is presented with equivalence proof established. Formulating the hierarchical equilibrium conditions in the light of Wardrop equilibrium principle, the equivalent variational inequality of the determinate equilibrium model, corresponding to the former transport network stochastic equilibrium model, is established. Secondly, a more practical bi-criteria bi-level programming model has been proposed for urban agglomeration three-dimensional logistics networks. A genetic algorithm to obtain approximate global optimum, fused in which a solution approach of Lagrangian dual that could overcome the defects of the widely-applied Frank-Wolfe method, is presented for the bi-level programming.(4) Optimal allocation approach for transport network resource and basic framework of transport network hierarchical planningAfter the analyses of bases for algorithm design from practical and theoretical aspects, a definition of hierarchy factor is formulated and two approaches to determine which are proposed. Furthermore, hierarchy factors are applied to design a new transport network structure optimizing algorithm (TNSOA) basing on the typical Dial's traffic assignment algorithm. The total impedance of the transport network obtained by the algorithm proposed decreases when upgrading the hierarchical level of link in the higher level and is less than by Dial's when the hierarchy factors are controlled in a certain domain, and that the total exhaust emission of the transport network obtained by TNSOA increases when upgrading the hierarchical level of link in the higher level and is anyhow less than by Dial's. The allocation of transport network resources can be effectively optimized and adjusted through controlling the network hierarchical level. All of the aforementioned investigations have finally contributed to an optimal allocation methodology of transport network resource.Then, basic framework of transport network hierarchical planning is investigated. After the passenger traffic forecast method studied under the guidance of the interaction mechanism between traffic system and urban spatial structure and the transit oriented development strategy, following with clarifying road function in different hierarchical level in the circumstance of location characteristics of land groups, constraining the cross, connection, conversion means between certain hierarchical levels, optimal allocation approach for transport network resource is invited to propose a basic framework of urban road network hierarchical planning method. The planning method and procedures are obtained through systematical analysis and quantitative modeling, guaranteeing the choiceness, optimization and dynamic adjustment of the whole road network designed.