Depending on the country, the letter attributed to a road may be part of a road grading system, be a
shortening for a
type of road especially in a foreign language or refer to a geographical zoning system, such as the
Appalachian Development Highway System or the
county highway systems of
California,
Iowa, and
Michigan in the United States.
International systems •
AH roads in the Asian Highway Network • CA-: highways part of the Central American highway network •
E roads in the International E-road network in Europe • EV: long-distance cycling routes in the
EuroVelo network of Europe • TAH: highways part of the
Trans-African Highway network Australia In Australia, road routes are allocated along sections of named roads, often along parts of multiple roads. Unlike many other countries, most highways in Australia tend to be referred to only by their names. State road authorities have separate numbering systems, for internal use only. File:AUS Alphanumeric Route A1.svg|Alphanumeric route (used nationally); may also be coloured orange-on-blue for tollways in VIC and QLD. File:New South Wales alphanumeric route B23.svg|Alphanumeric route which was previously used in the ACT & NSW before 2020 - progressively being replaced with the national standard. Note the white border. File:Australian national highway M31.svg|National Highway (alphanumeric): remains on old signs used in SA, QLD and VIC. File:Australian national highway 66.svg|National Highway (numeric): used in WA and partly QLD. File:Australian national route 80.svg|National Route: used in QLD and partly in WA and VIC; remains on old signs in ACT. File:Australian state route 3.svg|State Route: used in QLD, WA and Melbourne (VIC); also known as Metro Routes in Melbourne where it is slowly being phased out with alphanumeric routes. The first route marking system was introduced to Australia in the 1950s. National Routes were assigned to significant interstate routes – the most important road links in the country. National Route 1 was designated to a circular route around the Australian coastline. A state route marking system was designed to supplement the national system, for inter-regional and urban routes within states. Alphanumeric routes have been introduced in most states and territories in Australia, partially or completely replacing the previous systems.
National Routes and Highways In 1955, the Australian National Route Numbering System was introduced to simplify navigation across Australia. The National Route Numbers are marked by white shields that are present in directional signs, distance signs or trailblazers. The general rule was that odd-numbered highways travel in north–south directions and even-numbered highways in east–west directions, with only a few exceptions.
National Route 1 was assigned to a network of highways and roads, which together linked all capital cities and coastal towns circumnavigating the mainland. The National Route system initially linked the centres of towns and cities and terminated at the junction of other national routes, however many bypasses have been constructed since then. National Routes often terminated at the metropolitan city limits rather than the individual city centres. In 1974, the federal government assumed responsibility for funding the nations most important road links, with the introduction of the
National Highway. These highways were marked with distinctive green and gold route marker shields instead of the plain National Route shield. Though the National Highway system has been superseded in subsequent legislation, National Highway route markers are still used on many of the routes. Additionally, National Highways and National Routes have been phased out, or are in the process of being phased out, in all states and territories except Western Australia, in favour of the alphanumeric system. In the 1990s
Victoria and
South Australia also overhauled their systems. While South Australia discarded the National and State Route Numbering Systems, those shield-based schemes were retained in the Melbourne metropolitan area as the
Metropolitan Route Numbering Scheme. The route numbers used in the alphanumeric schemes were generally inherited from the original National Route Numbering System, with only a few exceptions, and prefixed with letters denoting their grade. For example, Western Freeway is M8 until Ballarat and continues beyond as A8 Western Highway. They are not used extensively in the Melbourne metropolitan area where the blue-shield metropolitan route system is retained for most routes. (They were phased out for motorways in the early 2010s. New alphanumeric numbers are appearing for other new roads, and cover plates for signs, possibly pointing to a future phase-out of the metropolitan route system altogether.) The National Highways were retained, but with the route numbers changed to alphanumeric designations (later to be passively phased out since 2014). New South Wales and the
Australian Capital Territory introduced the alphanumeric system from early 2013. There are no plans to introduce an alphanumeric route numbering system in
Western Australia.
Prefix letters In the alphanumeric systems, a letter denoting the route's construction standard and function is prefixed to the route number, creating an alphanumeric route designation. Normally, one of four letters may be used: • "M" routes are primary traffic routes, called motorways in some states. These are typically
dual carriageway,
freeway-standard highways, but may also be used for rural roads that are nearly at freeway-standard, or at least are dual carriageways.
Non-expressways • G, followed by 3 digits, stand for
guódào (), or
China National Highways. S routes stand for
shěngdào (), or provincial roads. • Roads 101 – 199 radiates from Beijing (G roads) or the provincial capital (S roads). • Roads 201 – 299 are north–south highways. • Roads 301 – 399 are east–west highways. • Roads 501 – 599 are spur routes. • County roads (
xiàndào, ) are prefixed with letter X. Township roads (
xiāngdào, ) are prefixed with letter Y. Village roads (
cūndào, ) are prefixed with letter C. Special roads (
zhuānyòng dàolù, ) are prefixed with letter Z.). In road signs the alphanumeric acronym is enclosed (not in the case of the 16 junctions) in a green octagon with a white acronym. The numbers of motorways and tunnels are assigned with a circular from the
Minister of Infrastructure and Transport to be published in the
Gazzetta Ufficiale.
Strade statali Strade statali are identified by a number and a name. In road signs and maps the number is preceded by the acronym SS, an acronym for
strada statale ("state road"). The nomenclature of the state highways managed by
ANAS generally follows the SS
n scheme, where
n is a number ranging from 1 (
Aurelia) up to 700 (of the
Royal Palace of Caserta) depending on the date of establishment of the state highway. Newly built ANAS roads, not yet classified, are identified by the acronym NSA, an acronym for
nuova strada ANAS ("new ANAS road"). In road signs the alphanumeric acronym is enclosed in a blue rectangle with a white acronym.
Strade regionali, strade provinciali and strade comunali Strade regionali are identified by a number. In road signs and maps the number is preceded by the acronym SR, an acronym for
strada regionale ("
regional road"). In road signs the alphanumeric acronym is enclosed in a blue rectangle with a white acronym.
Strade provinciali are identified by a number. In road signs and maps the number is preceded by the acronym SP, an acronym for
strada provinciale ("
provincial road"). In road signs the alphanumeric acronym is enclosed in a blue rectangle with a white acronym. Extra-urban
strade comunali may be identified by a number. In road signs and maps the number is preceded by the acronym SC, an acronym for
strada comunale ("
municipal road"). In road signs the alphanumeric acronym is enclosed in a white rectangle with a black acronym. Very rarely extra-urban strade comunali are marked with a number and with the abbreviation SC. File:Strada Regionale 1 Italia.svg|Road marker for
regional roads in Italy File:Italian traffic signs - segnale identificazione strada provinciale (figura II 259).svg|Road marker for
provincial roads in Italy File:Italian traffic signs - segnale identificazione strada comunale (figura II 260).svg|Road marker for extra-urban
municipal roads in Italy Malaysia Route numbering in
Malaysia is fairly simple.
West • All expressways (classified as an expressway by the Malaysian government) has a route number beginning with 'E', followed by a number. (e.g. and ) • All federal roads can have any route number except those stated below. (e.g.
Malaysia Federal Route 1) • Industrial roads has a four-digit route number beginning with '3'. • Roads build by the
Federal Land Development Authority has a four-digit route number starting with '1' or '2'. • Institutional facilities roads follow the normal numbering of federal roads. • All state roads begins with a letter other than 'E', followed by a number.
East Sabah • All major roads in
Sabah are federal roads. The route numbers are usually three-digits beginning with '5'. • Route 1, 13 and 22 belong to the
Pan Borneo Highway. • Institutional roads route numbers have three-digits beginning with '6'. • State roads normally begins with the letter 'SA', but some roads such as the Sapi-Nangoh Highway starts with the letter 'R'. Papar Spur-Pengalat-Lok Kawi Road and Beluran Road begin with the letter 'A' which is derived from the old route numbering scheme, though both of them are state roads.
Sarawak • Federal roads in
Sarawak are divided into sections. They have a main route number of '1', referring to the whole stretch of the route (i.e.
Pan Borneo Highway), followed by a dash (-) and the section number. (e.g.
Jalan Kuching-Serian) • Other roads can have any route number and are also divided into sections. • All state roads begin with the letter 'Q' followed by a number. Like federal roads, state roads may also be divided into sections.
Labuan • All federal roads in
Labuan have a three-digit number beginning with '7'.
Singapore Unlike in neighbouring Malaysia, Singapore does not use a route numbering system. Instead,
expressways in Singapore are assigned a three letter code, such as ECP for
East Coast Parkway.
United Kingdom The United Kingdom has two road numbering schemes, one for Great Britain and the other for Northern Ireland. Both schemes follow the same principles, but the numbers are independent and the same road number may be duplicated between the two schemes.
A, B, unnumbered, and unclassified roads In the United Kingdom, road numbers consist of a number up to 4 digits, prefixed with the letters A or B. The main road from
London to
Edinburgh was designated the
A1 in 1921; the "A" indicates a "trunk" or "principal" road, between regional towns and cities. In Great Britain, the A1, A2, A3, A4, A5 and A6 radiate out from London, or nearby, (in clockwise order) to points around the coast. Some A-roads, or sections of A-roads, are
dual carriageway, without being full motorways; some sections upgraded to motorway standards are designated in the form A1(M). B roads are minor roads; they may connect small towns and villages, or offer an alternate route to major roads. Classified unnumbered roads, unofficially called C roads, are smaller roads typically connecting unclassified roads with A and B roads. Unclassified roads are roads intended for local traffic; 60% of UK roads are unclassified, File:Essex County 609.svg|alt= County Route 609 route marker|County (Essex County, New Jersey) In the
United States, numbered highways belong to one of three or more systems of numbered routes, depending on the state. There are two national-level route numbering systems, the older
United States Numbered Highway System laid out in 1920s, and the newer
Interstate Highway System started in the 1950s. Additionally, every state in the U.S. maintains its own set of numbered
state highways. Some states have other systems as well, either a system of numbered
county highways or secondary state highways. A few cities also have numbered city highways; for example, the city of
Charlotte, North Carolina maintains
Charlotte Route 4. The U.S. Highway System, indicated by a white shield with black numbers, is based on a numbering grid, with odd routes running generally north–south and even routes running east–west. Primary routes have a one- or two-digit number, and are supplemented by
spur routes that add a hundreds digit to their parent route. Routes increase from east-to-west and north-to-south, such that
U.S. Route 1 follows the
Atlantic Seaboard fall line, while
U.S. Route 101 does the same at the Pacific Ocean Coast. Likewise
U.S. Route 2 runs near the
Canadian border, while
U.S. Route 98 follows the
Gulf Coast. Major cross-country routes end in either a "1" or a "0". For example,
U.S. Route 20 is a route that runs over from
Boston, Massachusetts, to
Newport, Oregon, while
U.S. Route 41 spans the country from
Miami, Florida, to the
Upper Peninsula of Michigan. Routes like
U.S. Route 141 and
U.S. Route 441 branch off U.S. Route 41.
U.S. Route 66, known as the "Mother Road", was a cultural touchstone that inspired literature, songs, and other media from its creation in 1926 until it was superseded by segments of the Interstate Highway System. Parts of the road have been designated "Historic Route 66". The Interstate Highway System, indicated by a red and blue shield with white numbers, is a system of entirely
freeways (unlike the U.S. Highway System, which is mostly undivided surface roads). The Interstate System is also based on a grid, with east–west routes bearing even numbers and north–south routes bearing odd numbers. In order to prevent confusion with the earlier U.S. Highway System, however, the Interstates are numbered in the opposite direction, such that the lowest routes numbers are in the south and west, and the highest numbers in the north and east. Major routes end in either a "0" or a "5"; for example
Interstate 10 spans the country from
Jacksonville, Florida, to
Santa Monica, California, while
Interstate 35 goes from the Mexican border to the Great Lakes. Like with U.S. Highways, subsidiary routes are numbered by adding a hundreds digit to the parent route. Because of the large number of these routes, three-digit numbers may be repeated within the system, but unique to each state. Additionally, the parity of the hundreds digit tells the nature of the spur route: odd hundreds digits like
Interstate 393 only connect to the system at one end (forming "spurs"), while an even hundreds digit like
Interstate 440 indicates that the highway connects to another Interstate at both ends (forming loops). The numbering system for
state highways varies widely from state to state. Each state decides how to number its own routes. Some maintain systems similar to the national road systems, based on a grid. Others number highways regionally, with similar numbers occurring in the same area of the state. Still others have no discernible system, with no connection between a route's location and its number. In addition to numbers, route numbers also use suffixed letters and banners appended to the tops of signs to indicate alternate routes to the main highway. For example,
U.S. Route 1A is the name given to many highways which are either older alignments of
U.S. Route 1 or provide an alternate route either around or through a city along U.S. Route 1's route. Banners are sometimes used to indicate alternate routes. Words like "
Alternate", "
Business", or "
Bypass" can be added to a sign to indicate such a situation.
Elsewhere Some countries, such as
Brazil, number their national highways by direction. (BR1xx = North/South highways, BR2xx = East/West, BR3xx = 'Diagonal' (i.e. NW/SE or NE/SW)).
Cyprus A, B, E, F system A stands for motorway and B is for main roads. E and F are for smaller local roads.
Estonian T system T is the prefix for all roads, however not represented on route shields. The prefix is mostly only used by the Estonian Road Administration and is not in common usage when referring to roads.
French A, N, D system A stands for "autoroute" (motorway), N for "national road", D for "départementale" road and C for "communale". France still uses
Route Nationale numbers from an 1824 revision of 1811 numbers made under
Napoleon.
Irish M, N, R, L system M stands for
Motorway,
N for
National primary road or
National secondary road,
R for
Regional road and
L for
Local road.
Jamaica A, B system Japanese C, E system C stands for circular,
E stands for expressway. These designations are used on most expressways in Japan outside of the
urban systems. The designations, depicted with a green rectangle with white numbers and letters, are used on guide signs as well as
highway shields.
Netherlands' A, N system A stands for "Autosnelweg" (motorway), N for
Non motorways. The A-codes use white letters on a red shield, the N-codes black letters on a yellow shield. Where a highway changes into a motorway or vice versa, it may continue to use the same number, but the letter and the color are switched. When the letter is followed by three digits, the road is typically a provincial road. When there are only one or two digits, it is typically a national road.
Philippines E, N system The Philippines' new route numbering system, started in 2014, for its network of
expressways (limited access roads) and national roads (of the primary and secondary types), uses E and N, respectively. National roads ("N" roads, of the primary and secondary designation) use white shields based on the Australian National Route shields, but signed with the number only, with N included for inventory purposes. Expressways ("E" roads) uses signs the same design as with national primary and secondary roads, but colored yellow, and unlike national roads, includes E to prevent confusion.
Polish A, S, DK, DW system • A stands for "
autostrada" (motorway) • S stands for "
droga ekspresowa" (expressway) • DK stands for "
droga krajowa" (national road) • DW stands for "
droga wojewódzka" (voivodeship/provincial road) There are also county roads (DP, "
droga powiatowa") and communal/municipal roads (DG, "
droga gminna"). However the numbers of these types of routes are only for administrative purposes, therefore not displayed on signage.
Senegal N, R system N stands for "national" roads while R is for "regional" roads.
South African N, R, M system N stands for national road, R stands for regional road and M stands for metropolitan road.
Spain A, AP, N system • A, followed by one or two digits, stands for "
autovía" (
dual carriageway). • If followed by three or four digits, it is road owned by a
regional government, usually
Andalusia or
Aragon, and may or may not be a divided highway. • AP stands for "autopista de peaje" (
toll motorway) • N stands for "nacional" (national), single carriageway road owned by the
national Government. National roads 1 to 6 are radial roads linking Madrid with major cities or borders with France and Portugal. All other roads are numbered with three digits. Other letters refer to the code of the
region or city that is served by the road. See for example
M-30, with M standing for
Madrid.
Turkey O, D, I system ) • O stands for "
Otoyol" (motorway) • D stands for "
Devlet Yolu" (expressways/major highways) • I stands for "Il Yolu" (provincial roads/minor highways)
Vietnamese QL, TL, HL system The following abbreviations appear on guide signs and kilometer posts: ; CT : (expressway) ; QL : (national road) ; TL or ĐT : or (provincial road) ; HL : or (rural district road) ; ĐCK : (canal towpath) ==See also==