40 years of the completed Kanetsu expressway

On this day, October 2nd, in 1985, the Kanetsu Tunnel, the second longest road tunnel in Japan, opened. And with it the entire Kanetsu Expressway between Tokyo and Niigata was opened. Prior to that one section had been opened since 1971. The Kan-Etsu Expressway is a national expressway that runs from Nerima Interchange (IC) in Nerima Ward, Tokyo, through Saitama and Gunma prefectures, to Nagaoka Junction (JCT) in Nagaoka City, Niigata Prefecture. It is abbreviated as KAN-ETSU EXPWY  or Kan-Etsu. The expressway number assigned to this route is "E17" presumably because its runs parallel to national route 17. 

The Kanetsu runs through one of Japan's snowiest areas, and there are many ski resorts along the route. Which means in winter it serves as the highway connecting the Tokyo metropolitan area with ski resorts. For this reason, many interchanges have been added to the expressway to try and relieve the congestion on parallel general roads that can be difficult to pass in winter. Famously, in December 2020, about 1000 vehicles were trapped on the expressway for hours after a trailer became stuck in the snow. The Japan Ground Self-Defense Force was deployed to aid in the distribution of supplies to the stranded drivers.

The Kanetsu expressway is the only national expressway in the radial direction of the metropolitan area that does not have a direct connection to the Metropolitan Expressway, and so until it was connected to the Tokyo Outer Ring Expressway in recent years, there was always heavy traffic congestion at the Nerima IC, but especially in winter.