EQUILIBRIUM LAND USE PATTERNS IN A NONMONOCENTRIC CITY

In the 1970's, a new genre of mathematical urban land use theory, called the new urban economics (Mills and MacKinnon [S]), was developed. The principal characteristics of those models are the monocentricity of the city, the uniform transportation system, the homogeneity of households and production firms, and so forth (Richardson [ 161). Among these, the assumption of monocentricity seems t o be very crucial to the formulation of the models. By monocentricity, we assume that the city has a single, pre-specified center, the CBD, which has a fixed size and employs the city's entire labor force. This assumption greatly simplifies the analysis: for example, commuting trips can be exactly specified if the residential locations are known, and with the assumption of a linear or circular city, the spatial characteristics of each location in the city can be described simply by the distance from the CBD. However, from the viewpoint of theoretical completeness, the centrality or noncentrality of a city should be explained within the framework of the model, which incorporates interdependences among economic activities, without prespecified locations of employment activities. And, if the model succeeds in clarifying the conditions for the existence of the CBD, we can not only judge the adequacy of the monocentric assumption adopted by the current urban land use models but also step forward to a more fruitful theory which is capable of explaining various kinds of nonmonocentric phenomena. Moreover, from the viewpoint of reality, monocentricity is an implausible assumption. In the face of the tendency of increasing decentralization and a decline of the role of the CBD as a single focus of employment activity (Mills [9]), urban land use models based on the monocentric assumption are clearly inadequate for analyzing recent cities.' Thus, both from the viewpoints of theoretical completeness and practical usefulness, the development of nonmonocentric models of urban land use is needed. There have been a few works which attempt to relax the monocentric assumption in two different ways. One approach is to introduce pre-specified