Compact city is thought as an important policy so as to cut down the urban maintenance management cost. But, the process of the urban compactization assumes to need a lot of cost. We should evaluate the compact city not only by the operation cost but also by the long term cost including the process of the urban compactization.
In this case study, we created the 3 scenarios for the Nagaoka city toward the year of 2050, which are different in the degree of compactness, and evaluated them both in the compatcization period and the following operating period by the construction cost of urban facilities, infrastructure and all buildings of the target area including new built, retirement, and maintenance. The result is that the middle compact Polycentric scenario spend 19 years and the most compact Monocentric scenario spend 23years to recover the cost of compactization.
We also calculated the administrative cost (construction and maintenance cost of the urban facilities, infrastructure and government buildings ,and compensation cost for moving) to realize the compact city of Polycentric scenario. The construction cost and compensation cost for peoples who move from suburbs to downtown could recover for 12yeas by saving the maintenance management cost and increasing property tax, if the compensation were for the values of the lands the moving people had in the suburbs before moving.