The document discusses converting Tokyo's central ring road of the Metropolitan Expressway into a rescue route that can be used to reach areas devastated by an earthquake. It proposes building the road underground and turning the space above into a green sky park. This would help address issues of self-defense forces accessing hard-hit areas and allow the road to serve dual purposes as both an expressway and disaster relief corridor. It also notes the road was originally built for the 1964 Tokyo Olympics but has since faced controversy over its urban impact.