Prefectural roads (都道府県道, todōfukendō, singular depending on the type of prefecture: todō, dōdō, fudō or kendō) in Japan are roads usually planned, numbered and maintained by the government of the respective prefecture (-to, -dō, -fu or -ken), independent of other prefectures – as opposed to national roads (kokudō), which in legal terms include national expressways (kōsoku jidōsha kokudō), and municipal roads ([ku]shichōsondō). Where a national or prefectural road runs through the territory of a designated major city, the city government assumes part of the responsibility for these roads. By length, 10.7 % of public roads in Japan were prefectural roads as of 2011; by usage, they carried more than 30% of all traffic volume on public roads as of 2007.[1]
Prefectural roads are marked with a blue hexagon, with the number centered. Most usually end at another prefectural road, or national route, or occasionally at or very close to a Japan Railway station.
Numbers are used only once in each prefecture, regardless of where the road begins or ends. If a prefectural road crosses into another prefecture, its number is not necessarily reused by the prefecture it crosses into, but many prefectural roads running through multiple prefectures are coordinated to share a number. For example, the "Fuchū-Sagamihara Line" (fuchuu-sagamihara-sen, 府中相模原線), which connects Fuchū City in Tokyo and Sagamihara City in Kanagawa Prefecture, starts as Tokyo Prefectural Road 20 but ends as Kanagawa Prefectural Road 525, while the "Sano-Koga line" (sano-koga-sen, 佐野古河線), which connects Sano City in Tochigi Prefecture and Koga City in Ibaraki Prefecture, is continually designated as Prefectural Road 9 in all four prefectures it runs through, namely Tochigi, Gunma, Saitama and Ibaraki.
Some prefectural roads will also at times run for a short distance concurrent with a national route, but it is more common to see this with other prefectural roads.
Numbers used for national routes that run through a prefecture are often duplicated by prefectural routes but a national route and a prefectural route bearing the same number rarely if ever meet or cross each other.
