Japan National Route 42

, also called Kumano Kaidō or Tropical Route is a national highway connecting Hamamatsu, Shizuoka and Wakayama, Wakayama in Japan. Part of the route requires crossing Ise Bay on the Ise-wan Ferry.
It is the 8th longest national highway in Japan.
History.
Route 42 was originally designated in January 1945 as a section of Route 41 (the Kumano Highway), which ran to Tokyo. This ran concurrent with Route 1 (now Route 1/Route 23). On 18 May 1953 Route 41 was classified as a Class 2 highway and redesignated as Route 170, which was later redesignated as Route 42 when the route was promoted to a Class 1 highway.