Japan’s Expressway Numbering System

What is the Expressway Numbering System?

The Ministry of Land, Infrastructure, Transport and Tourism (MLIT) is introducing this new numbering system, a scheme that combines route numbers with route names, to Japan’s growing expressway network in order to make it easier to understand for all expressway users, including foreign visitors to Japan.

Routes covered by the Expressway Numbering System

〇　Routes forming the arterial high-standard highway network (“national expressways” and “national highways for motor vehicles only”) as well as regional expressway networks that supplement this network
〇　Routes forming expressway networks that provide access to major airports, harbors, and tourist areas from the arterial high-standard highway network
(*Urban expressways that are already numbered [e.g., the Tokyo Metropolitan Expressway, Hanshin Expressway, etc.] are excluded from the new Expressway Numbering System.)

Description of Expressway Numbering

Basic features of the Expressway Numbering System

１．It’s easy to get used to.
　●The system uses the national route numbers (one or two digits) of main national routes that are already familiar to local residents.

２．It’s simple and easy to understand.
　●As a rule, numbers are limited to one or two digits.
　●Routes having similar functions (for example, they have the same start and end points) are grouped into route “families.”
　●Road types and functions are indicated with alphabetic letters.
　　・The letter “E” appearing at the beginning of a number indicates an expressway.
　　・The letter “A” appearing at the end of a route number indicates a grouped route (i.e., road in a route family).
　　・The letter “C” appearing at the beginning of a route number indicates a circular route.

３．It represents the structural layout of the nation.
　●It establishes route “start” and “end” points to allow representation of the nation’s structural layout using major expressway numbers.

Specific numbering classifications

(1) Route that runs parallel to a single- or double-digit national highway	The number of the national highway is assigned to the route.	Examples: Tomei Expressway *The parallel route is National Route 1.
(2) Route that is grouped with (i.e., is in the same “family” as) a single-digit national highway	The Shin-Tomei Expressway and Shin-Meishin Expressway, which run parallel to the Tomei Expressway and Meishin Expressway (both “1”), respectively, are grouped with those expressways with the number “1A.” Similarly, the Chugoku Expressway, which runs parallel to the Sanyo Expressway (“2”), is grouped with that expressway with the number “2A.”	Shin-Tomei Expressway Shin-Meishin Expressway Isewangan Expressway
		Chugoku Expressway Kanmon Expressway
	In the cases of routes “3,” “4,” and “5,” the number is assigned to the route that was built first. Newer sections that run parallel to the existing national highway are grouped with that national highway with the letter “A.”	Minami-Kyushu Expressway Tohoku Jukan Expressway Hachinohe Route (Ashiro - Aomori) 〔Hachinohe Expressway, Aomori Expressway〕 Trans-Hokkaido Expressway (Kuromatsunai - Sapporo) 〔Sasson Expressway〕
(3) Circular route	Circular routes in the Tokyo and Nagoya metropolitan areas have their function indicated with the alphabetic letter “C.” Numbers are assigned with consideration for consistency with other existing urban expressway circular routes.	Tokyo-Gaikan Expressway Metropolitan Inter-City Expressway (Ken-O Expressway) (Kamariya - Kisarazu) Tokyo Wan Aqua-Line , Tokyo Wan Aqua-Line Renraku Expressway Nagoya Daini Kanjo Expressway Tokai-Kanjo Expressway
(4) Route numbered by collectively viewing routes that run parallel to a single- or double-digit national highway as one	The Hokkaido Junkan Expressway is assigned the number “5” because it is part of the main expressway layout of the nation and Hokkaido.	Hokkaido Junkan Expressway 〔Hokkaido Expressway, etc.〕 (National Routes 5, 37, 36, 12, and 40)
	Routes that generally match the direction of a double-digit national route within the same region are given the number of that national route.	Examples: Asahikawa-Monbetsu Expressway Tokai-Hokuriku Expressway
	If the parallel national highway has a three-digit number or is a route in which the national highway route number of the parallel national highway is assigned to another route, and there is an adjacent national highway, the relevant national route number is extended.	Examples: Keiyo Road, Tateyama Expressway, Futtsu-Tateyama Road (National Routes 14, 16, and 127)
(5) Other route	Other routes are numbered with a double-digit number of 59 or higher that is not already in use as a national highway number.	Example: Hakodate-Esashi Expressway