抄録
The recent burst of the land price, which started in Tokyo Central Business District, created severe difficulties to many local municipalities. When they engage in the future city planning, they have to project the future trends of land price and of other related variables as the basic data to evaluate the future development of the local economy.
For this purpose this paper presents an empirical study with the quantitative model in which land price plays an important role. I took up the case of Mitaka city, which is located at the western suburb of Tokyo CBD and served as a bed-town for decades, and is currently experiencing a big land price burst. I divided Mitaka into four districts based upon the different trends of land price and density of population. I collected the mesh data of land prices and population, and then aggregated for four districts, and used them in combination with other variables to construct the model. The model cosists of five blocks; demography, industrial activities, land use and land prices, households, and public sector. The number of equations is 42 including definitions. In causal chains the land price and population of each district is explained by aggregate variables as well as the land price of CBD. Then two avarage land prices are defined by weighting; each weighted by population or area of districts. The former expresses the actual burden of land cost for residents and the latter expresses the land cost of new acquisition. When the land price was used as an exogenous variable in other equations, I selected one of the two which gave the better fitting.
One of the feature of suburban city is the strong ties with CBD, so I took up many indices which represent the trends of Tokyo CBD as well as Japan and used as exogenous variables to stress these ties.
After confirming the sufficient fit of the model for 1971-85 by the final test I used the model to produce a conditional forecast until 2000 assuming the reasonable trends for Japan and Tokyo CBD. The results showed a strong change from bed-town to a commercial area which is accompanied by changes in land use in future. The population will increase by 15794 (9.8 percent of current figure). The model projects the population and land price by district, thus is able to assess the possible effects of changing regulations for construction. Now the city authority of Mitaka plans to relax the building coverage ratio. Another projection predicts that this deregulation will produce the further increase of population by 3768 out of which 3254 is the direct effect and 514 is the indirect effect. Thus the deregulation of buildings may improve the current housing condition, but the effect will be largely diminished through accelerating social population inflow.
