Abstract:<\/strong><\/p>\n Japan\u2019s economy is entering a new phase of economic growth after the so-called \u201clost 15 years\u201d since 1990. Particularly Tokyo and Aichi prefectures have been drawing attention as engine of new economic growth in Japan. Although the recovery of Japan\u2019s economy has resulted in an increase in the demand for transportation, construction of new roads in region-wide areas has been in a serious situation. It is attributed to a decreasing trend in Japan\u2019s population and aging which will cause Japan\u2019s national budget being reduced in the future. Due to this situation, stricter economic assessment of new roads development in region-wide areas has particularly been required than before. Taking into account these backgrounds, this article aims to present a model integrating the equilibrium concepts of economic and transport network. Moreover this model will be able to be extended into a full spatial equilibrium model. And then setting San-En region in Aichi and Shizuoka prefectures as a study area which consists of many urban and countryside areas, this study also aims to measure the economic impacts of construction of new roads development in this region.<\/p>\n