## Summary

According to the questionnaire survey on the private businesses, who are the users of infrastructures, we confirmed that they have high expectations on infrastructures, such as traveling (transport) time and the reduction of costs $ ^{Note\ 52} $ , for increasing the productivity of corporate activities, indicating diverse and close relation with the infrastructures. On the other hand, for the proposal of a smart use of infrastructures, not many private businesses take an active stance indicating their willingness to participate $ ^{Note\ 53} $ and many answered “Neither.”

In addition, According to monitor survey targeting citizens (individuals), as for the maintenance management of infrastructures through resident participation, more than 60% of the citizens wish to take part, indicating a high level of willingness to participate Note 54.

From a historical angle, during the Edo period, it was often that residents developed bridges on their own for utilization to support their economic activities. For instance, 90% of bridges in Osaka were built by residents, which are called town bridges. The 808 Bridges of Naniwa supported the residents' economic activities and played an important role in supporting the development of daily lives and cities $ ^{55} $ . In the Osaka city surrounded with many waterways, the bridges are required infrastructures. It is thought that the merchants at that time had good understanding of the functions, making the best of functions, supported economic activities and contributed to the development of a mercantile city, Osaka.

At present, there are many cases similar to Edo period, such as the location of a new plant by FANUC Corporation in Tochigi, the construction of a new plant by Daihatsu Motor Kyushu Co., Ltd. in Nakatsu Port in Oita and the transfer of headquarters in the same area, as well as the advancement of Niigata JAMCO to Murakami, Niigata. The private businesses build new plants, etc. in order to utilize the convenience in a proactive manner $ ^{Note\ 56} $ , by keeping with or expecting the development of transportation infrastructures such as roads, ports and harbors.

Although historical backgrounds vary, the above cases share a common ground that the private entities recognize the functions of infrastructures to make maximum use of infrastructures, and as a result, it leads to increase economic activities and corporate activities.

In this way, if the corporations focus attention on stock effects by infrastructure development to make maximum use of the effect, it would appear that it leads to an increase in the productivity of corporations. For the administration, it is important to approach the visualization of seeing and showing stock effects.

For instance, as introduced in Section 1, Chapter 2, with the use of big data, questionnaires and other various methods, we can expect that the stock effects are understood objectively as much as possible to make available to the public (“visualizing”) and by providing stock effects more effectively to share with users (namely “visualizing”), the users of infrastructures can realize the stock effects much further.

For the future, based on the perspectives above, it is required to increase social-based productivity and contribute to sustainable and strong growth by putting effort into strategic infrastructure development, such as “smart investment and use” and “visualizing” the stock effects.