New Bypass "Shinano-Ōmachi" to Be Built as Part of Matsumoto–Itoigawa Connecting Road

The Ōmachi Construction Office of Nagano Prefecture held a briefing on June 14, 2026, to explain the preferred route for a new bypass that will form part of the Matsumoto–Itoigawa Connecting Road, also known as the "Matsuito Road." The selected "C-route" extends about 8.6 kilometers, crosses the Takase River, and connects to National Route 148 near Lake Kizaki. This bypass, designated "Shinano-Ōmachi," aims to improve traffic convenience in the Ōmachi city area and link the Chūō Expressway with the Sea of Japan.

The planned route runs parallel to the JR Ōito Line (Matsumoto–Itoigawa), offering a shorter connection between the Chūō Expressway and the Sea of Japan compared to existing routes such as the Nagano Expressway and Jōshin-etsu Expressway. Combined with the San'en Nanshin Road linking to the Shin-Tōmei Expressway, the corridor will eventually form a north-south route connecting the Pacific Ocean and the Sea of Japan along Japan's central tectonic line.

Within Azumino City, a 4-kilometer expressway section called the "Azumino Road" was already approved in 2022. From there to Ōmachi City, the existing road will be used (including upgraded sections), while a new bypass will be built through central Ōmachi. The C-route was selected in December 2025 from three proposed alignments, prioritizing convenience for the city center. It runs west of the Takase River, perpendicular to National Route 147, crosses the Ōito Line, spans the Takase River, and reaches National Route 148 near Lake Kizaki.

Construction Office officials stated that after gathering public input and discussion, they intend to prepare a draft urban plan to handle individual consultations and proceed with formal planning. The draft will be released for public comment before the project seeks official designation as an urban planning road for new construction. On the Niigata Prefecture side, the route is largely finalized; a 5-kilometer bypass connecting to the Hokuriku Expressway already includes a 1.3-kilometer section that opened early as a prefectural road bypass. In the border-area village of Otari, the 2.0-kilometer "Uchū Bypass" on National Route 148 opened in November 2025, along with the "Otari Road" bypass, both part of the Matsuito Road.