If the shield method is used, this issue doesn't arise; however, Kyoto City gave the reduction of direct expense for construction the first priority and decided to employ an open-cut method for a substantial portion of the construction site (particularly that of Oshikoji-dori Street, which was included in the district of Nijo-jo Castle which was a national historic site).
シールド工法による工事の場合にはこの問題は発生しないのであるが、京都市は工事の直接経費の節減を優先し、工区のかなりの部分（特に、国の史跡の「旧二条離宮〈二条城〉」の区域に入っていた押小路通）を開削工法で掘削することにした。