Yamanashi Prefecture is planning to build a new tunnel connecting Tsuru City and Doshi Village. The planned route is assumed to be from the Sugano district of Ono, Tsuru City on the Prefectural Road Tsuru Doshi Line to the vicinity of Itabashi on National Route 413 Doshi Village. The total length is about 3.4 km, of which about 3 km is a tunnel section. The prefectural government plans to hold a local briefing session in July and aim to commercialize the project in fiscal 2024. The plan is to start construction in about three years after commercialization.
Governor Kotaro Nagasaki made the announcement at the prefectural assembly on the 23rd. The new tunnel is "(tentative name) Shindozaka Tunnel". The current Tsuru Doshi Line on the prefectural road has many sharp curves and steep slopes, and the impact of rainfall regulations, snow accumulation, and freezing is an issue. The purpose of the construction of the new tunnel is to fundamentally eliminate restricted sections and improve driving safety.
In January 2020, the prefecture launched the Tokyo-Yamanashi/Nagano Transport Resilientation Project with the Kanto Regional Development Bureau and others. has been proceeding. Among them, National Highway 413 and Prefectural Road Tsuru-Doshi Line have been positioned as alternative routes for National Highway 20, and consideration has been given to the abolition of rainfall regulations, the development of the Doshi Bypass, and new tunnel plans.
