The Yatomi - Aioiyama line is a city-planning road that was notified in 1957 and subsequently prepared by land readjustments. Currently, approximately 900m of road pass in the inside of the Aioiyama green area has not been constructed. The surveying briefing session for inhabitants was held in July 1992, the project was authorized by the Ministry of Land, Infrastructure and Transport in September 1993, and the project briefing session for inhabitants was held in September 1993. The site purchase has been completed. At the May 2000 briefing session, inhabitants of the area began voicing dissenting demanding the conservation of the natural environment of this green area. The inspector system serves as the third party, independent of both the administration and the inhabitants. Before finalizing the geometric line form of the road to be constructed, some surveys of animals and plants found along the walking trails carried out intensively in the northern area, which is approximately 50 ha, of the Aioiyama green area. The natural environment inspector submitted a plan for changing the geometric line form of the road decided upon by city planning, and it was approved by the city planning council. If the shelter structure or the retaining wall structure is adopted at the location where large slope faces are produced by excavation or landfill, and if the bridge structure is adopted at the place where stream-lines and walking trails intersect, it leads to a reduction of approximately $40\%$ in the areas for which change is planned. Furthermore, approximately $20\%$ of the area to be changed is restored by returning soil to the roof of the shelter.