mature society while valuing more of the aspects of “preservation,” such as existing stock utilization and harmony with natural environments. Responsive to this move, National Spatial Strategies $ ^{Note 3} $ were formulated in 2008, which have been enforced to date.

Because the work of developing, maintaining and managing infrastructures generally is not compatible with market principles, it has been carried out at the primary initiative of public offices, but a review of the shares of the responsibility between the governmental and private sectors has been underway to reflect continuing global trends towards privatization. In railways, for example, a JNR privatization reform that took place in 1987 put an end to the 115-year-long history of national railways that had been owned and run by the nation since 1872, passing over the railway services to a newly incorporated JR. The New Tokyo International Airport Authority dissolved in 2004 to launch Narita International Airport Corporation.

As a scheme of infrastructure development, maintenance and management, PFI has launched since 1999 pursuant to the provisions of the Act on Promotion of Private Finance Initiative since it came into being first in the U.K. In 2011, efforts followed to encourage further PFI usage, which included expanding the scope of facilities that qualify for PFI and inaugurating a system of suggestion by private entrepreneurs and a right to administer public offices, etc.

Thus, Japan has such a long history of infrastructures development, maintenance and management dating back to the ancient times that its infrastructures have been developed, maintained and managed to suit the social situations of the times, as well as the relationships between the nation and locals and between the governmental and private sectors. The process of plotting the futures of infrastructures maintenance and management should be pursuing the most efficient, most effective way of management to address the challenges of the times with due regard given to such historical changes.

## 2 Roles of Social Infrastructures

As reviewed above, the lasting development of infrastructures from the olden days afterward has been motivated by expectations of their effects to revitalize our economic activities and enrich our living for long periods. While the effects of treasury disbursements are often discussed with regard to the flow effects $ ^{Note 4} $ , their stock effects are reviewed below.

## (1) Stock effects of social infrastructures

The stock effects of social infrastructures can be broken down into two categories (Figure 1-1-16):

①Productivity effect - Social infrastructures boost the productivity of economic activities by cutting transit times, reducing transport costs and so on, encouraging economic growth.

②Welfare effect - Social infrastructures help augment the quality of life by enhancing amenity, improving the hygienic environment, furthering safety in times of disasters and so on, making for better economic welfare.

Various studies have dealt with the stock effect so far. Particularly, a number of studies have focuses on the productivity effect. Productive factors that create economic growth can be classified into labor force, capital and all other productive factors (TFP $ ^{Note 5} $ ). Studies on productivity

effects grabbed attention when the possibility of explaining the fall in the rate of TFP in the 1970s and after from its level in the 1960s with reference to the then disquieting issues of aging social infrastructures and their slow development