Urban Commercial Land Use And Transportation Network Equilibrium Analysis

Commercial enterprises' location distribution and consumers' trip distribution in a city constitute the urban business land use system. On one hand, due to the impact of travel cost, employment location and residential location, the spatial distribution of consumers is not identical and has the characteristic of aggregation. Because of the capital profit chasing, the aggregation of consumer demand often leads to the aggregation of enterprises. One the other hand, enterprises'concentration means more shopping options and greater shopping convenience for consumers, thus enterprises' concentration results in consumers' aggregation in turn. In summary, the business land use model provides an integrated framework to study the spatial distribution of urban business and social activities, and thus further provides the theoretical and decision support to the comprehensive and sustainable land use planning and commercial development of a modern city.First, we study the interaction between small and medium-sized enterprises' location distribution and consumers' trip in an urban transportation network. A business land use equilibrium model is proposed, which puts consumers' traffic equilibrium and firms'competitive location firm in a unified framework. By reformulating the equilibrium issue as a variaitonal inequality, we investigate the existence and uniqueness of equilibrium solution. Additionally, the associated congestion pricing principle is studied. When simultaneously imposing charges on travelers and companies is allowed, we prove that there exists an optimal congestion pricing scheme that can derive a land use equilibrium pattern toward an overall system optimum pattern. The pricing scheme's economic meaning is also investigated. Finally, a simple numerical example is used to demonstrate that the optimal congestion pricing scheme can indeed reduce the social cost and balance the distribution of firms and travelers efficiently.Second, by further considering firms' relocation cost and business center capacity constraint, we extend and improve the preceding land use model. First of all, we propose a deterministic equilibrium model where the relocation cost between any two business centers is explicitly considered, and establish the equivalent variaitonal inequality. In addition, the business center capacity constraints, which consist of passenger flow capacity constraint and firm flow capacity constraint, are further incorporated into the first deterministic model. These constraints are showed to provide two important findings. The first finding is that the Lagrange multiplier associated with the passenger flow capacity constraint of a business center corresponds to travelers'queuing time if the amount of travelers in this center reaches the maximum passenger flow capacity and the queuing phenomenon occurs at equilibrium. Furthermore, we find that the firm capacity flow constraint for a business center will derive the endogenous location transfer market and corresponding location transfer agreement for firms if the capacity is reached at equilibrium. The equilibrium location transfer price of a business center is proved to be equal to the Lagrange multiplier associated with the firm flow capacity constraint of this center. Thus the location transfer market is endogenous. Besides, we extend the above deterministic models to the stochastic case to capture the stochastic behaviors and of travelers and firms in practice and investigate the properties of stochastic equilibrium. At last, a numerical experiment is provided to study the impact of relocation cost on firms' location distribution and relocation behaviors and consumers'trip distribution in a simple network.Third, we develop a bi-level business land use model to study the interaction between large oligopolistic enterprises'competitive location and residents'trip in an urban transportation network. In the upper-level problem, each oligopolistic firm non-cooperatively seeks to attract customers and maximize individual net profit by designing his optimal location distribution scheme in the network according to other firms'decisions, and the competitive location among firms is modeled as a generalized Cournot-Nash game. In the lower-level problem, residents'response to the location distribution of firms is formulated as the stochastic user equilibrium with shopping trip chains. Corresponding business centers are included into trip chains to describe residents'consumption choice and shopping order in their trips. As a result, the bi-level overall equilibrium problem for firms and residents is formulated as an equilibrium problem with equilibrium constraints (EPEC) model. Characterizing the upper-level problem and the low-level problem by a variational inequality and a strict convex optimization problem respectively, we study the existence of solution of EPEC and the economic implications of the first order optimal condition of each firm. Based on the sensitivity analysis of the stochastic user equilibrium problem, we propose a heuristic solution algorithm. Finally, a simple numerical example is given to investigate the characteristics of firms' location distribution and residents' trip distribution under different travel demand pattern and analyze the impact of transportation accessibility on the development of urban business centers.