Kan-Etsu is the kanji acronym of Kantō region and the old Echigo Province comprising modern-day Niigata Prefecture. Officially, the Kan-Etsu consists of two routes. Both begin in Tokyo and end in Niigata Prefecture. The Kan-Etsu Expressway Niigata Route consists of the entire Kan-Etsu Expressway from Nerima to Nagaoka, as well as the Hokuriku Expressway beyond Nagaoka to its terminus in the city of Niigata. The Kan-Etsu Expressway Jōetsu Route is concurrent with the Niigata Route until Fujioka Junction, where it branches off as the Jōshin-etsu Expressway and traverses Nagano Prefecture to its terminus in Jōetsu, Niigata. The remainder of this article will focus on the Niigata Route section between Nerima and Nagaoka.
Overview
The expressway begins in Nerima Ward in the north of Tokyo; the Kan-etsu is the only national expressway linking Tokyo that does not have a direct connection with the urban Shuto Expressway network. A junction with the Tokyo Gaikan Expressway near the origin links the Kan-etsu with other expressways serving northern parts of the Tokyo urban area. From here the expressway follows a roughly northwesterly course to its terminus in Niigata Prefecture, passing through central areas of Saitama Prefecture and Gunma Prefecture. In Gunma the Kan-etsu provides access to Nagano Prefecture by way of the Jōshin-etsu Expressway at Fujioka Junction, and completion of the Kita-Kantō Expressway in 2011 will facilitate access to Tochigi Prefecture and Ibaraki Prefecture. The mountainous area separating Gunma and Niigata Prefectures is traversed by the Kan-Etsu Tunnel, the second longest road tunnel in Japan. The expressway then passes through southern Niigata Prefecture before terminating at a junction with the Hokuriku Expressway in Nagaoka. The expressway parallels National Route 17 and the Jōetsu Shinkansen of East Japan Railway Company for most of its length. The first section opened in 1971 and the entire route was opened to traffic in 1985. The route is six lanes from Ōizumi Junction to Shibukawa-Ikaho Interchange, and all other sections are four lanes.
