||The examples and perspective in this article deal primarily with the English-speaking world and do not represent a worldwide view of the subject. (January 2011)|
A route number or road number is often assigned to a stretch of public roadway. The number chosen is often dependent on the type of road, with numbers differentiating between interstates, motorways, arterial thoroughfares, two-lane roads, and so forth.
- 1 United Kingdom
- 2 United States
- 3 Canada
- 4 Hong Kong
- 5 Malaysia
- 6 Australia
- 7 Germany
- 8 Elsewhere
- 9 See also
- 10 Further reading
In the United Kingdom, the road number consists of a letter followed by a number of up to 4 digits. For example, the historical main road from London to Edinburgh is called the A1, the "A" in Britain indicating a first class route, classified as more important than "B" roads. The A2, A3, A4, A5, A6 also radiate out from London (in clockwise order) to points around the coast. All classified roads starting in the zone between the A1 and the A2 begin with the figure 1 (A137, B1412), etc. Scotland is similarly divided into zones by the A7, A8 and A9 which radiate out from Edinburgh. Motorways are marked by an M, for example the M25, which forms a ring road around London. Motorways are fast freeways and are generally larger than "A" roads. Motorways follow different zoning and numbering systems from "A" and "B" roads.
A similar clock-face zonal system is used in many other European countries (for example, Spain).
In other countries, such as the United States, the situation is a bit more complicated. The numbers can be broken up into several major classifications, such as Interstate highways, or high-speed limited-access highways. For instance, the Interstate between Boston and Seattle is called Interstate 90. The United States Highways are often more local routes that can span multiple states and can include multiple roadway classifications. An example of this is the U.S. Highway linking Maine to Florida called U.S. Route 1. There are also state highways that are usually more minor than those of U.S. highways. These are often titled with the state name followed by the route number; Kentucky Route 67 indicates a Kentucky state road numbered 67.
Under the current numbering system for Interstate highways, odd numbers generally indicate a north–south route, and even numbers mean an east–west route. The numbering system creates a sort of grid; east-west Interstates increase in number as one goes north, and north-south Interstates increase in number as one goes east. For example, Interstate 4 is in central Florida, while Interstate 94 runs in the northern part of the country. Also, Interstate 5 travels along the Pacific Ocean while Interstate 95 runs up the East Coast. Conversely, north–south U.S. Highways increase in number as one goes west (U.S. Route 1 parallels Interstate 95 and U.S. Route 97 runs in the Pacific Northwest) and the number of east–west U.S. routes increase as one goes south (U.S. Route 2 travels along the Canadian border and U.S. Route 98 runs along the Gulf of Mexico). States may or may not follow the odd and even rules and usually do not number their routes according to a grid. Some exceptions are Iowa, which uses a grid to number its county routes, and Ohio, which has "clusters" of similarly numbered routes.
The numbering system for state highways varies widely from state to state. A state may choose to use letter prefixes for all, some, or none of its state roads. For example, the Virginia Department of Transportation does not use letter prefixes for state primary or secondary routes, but does use an "F" prefix for frontage roads. Although the state's two-letter designation usually becomes a prefix for the route, some states, like Michigan, prefer to use a single-letter prefix (such as "M-28"). Indeed, a state may choose to give a route an entirely alphabetic designation, such as the lettered county routes in Wisconsin and the Missouri supplemental routes.
Some states (Southern and Midwestern states in particular) tend to use the term "Highway" for state routes and their sections of U.S. Highways, while others prefer the term "Route."
Some routes may carry a letter suffix, such as E/W (for East/West) or N/S (for North/South). Other lesser-known suffixes include A (for Alternate), B (for Business) and C (for City), but not all states practice this convention. For example, in New York State, there has been or currently are routes 17, 17A, 17B, 17C, 17D, 17E, 17F, 17G, 17H, 17J, 17K, and 17M.
Complicating the issue further is the fact that some states have distinct numbering systems for primary and secondary routes or for state routes and county highways. For example, in Virginia, the primary and secondary road systems have numbering ranges that are, with rare exceptions, mutually exclusive.
The Trans-Canada Highway system is made up of federally maintained highways, and is the only system that uses route numbering that spans multiple provinces. The provincial highways are assigned numbers by their respective provinces.
All provincial highways are 'Primary Highways'. They are divided into two series', and sub-series'.
- 1-216 Series — core highway network
- Hwy 1-100 — intercity
- Hwy 201, 216 — orbital routes
- 500-986 Series — local highways
- Hwy 500-699 — west-east routes
- Hwy 700-899 — south-north routes
- 900 and X series — potential realignments and extensions
Owing to the mountainous terrain in the province, route numbers are assigned on a mostly ad hoc basis, and vary between west-east and south-north routes. They currently span from 1-118, except for Hwy 395 which is a counterpart of US 395. Some routes are grouped in numerical patterns (e.g. Highways 9, 11, 13, 15, 17, and 19 are North-South routes with values increasing by increments of two moving West). British Columbia formerly had "400 series" of highways similar to Ontario, but that scheme was dropped in 1973.
Provincial Trunk Highways (PTH) are divided into two series'.
- PTH 1-199 — primary highways
- PTH 1-89 — intercity
- PTH 100, 101, 110 — loop routes
- PR 200-699 — secondary highways
Provincial highways are divided into three series'.
- Route 1-99 — arterial highways
- Route 100-199 — collector highways
- Route 200-999 — local highways
Newfoundland and Labrador
Provincial highways are divided into three seres'.
- Main highways have varying numbers
- Regional roads are numbered by region
- Route 2-203 — Avalon Peninsula
- Route 204-205, 230-239 — Bonavista Peninsula
- Route 210-222 — Burin Peninsula
- Route 301-346 — Kittiwake Coast, Fogo Island, & Twillingate
- Route 350-371 — Exploits River Valley & Bay d'Espoir
- Route 380-392, 410-419 — Baie Verte
- Route 401, 420-438 — Great Northern Peninsula
- Route 402-407, 440-490 — Western Newfoundland
- Route 500-520 — Labrador
- Local highways are based on intersecting primary routes and numbered with extension (i.e. 210-1)
Provincial highways are divided into five series'.
- 100 Series — arterial highways
- Trunk Highways
- Route 200-399 — collector highways
- Scenic Routes are unnumbered
- Local roads are unnumbered
Provincial highways are divided into four classes.
- Hwy 2-148, 400-427 — King's (primary) highways
- Hwy 2-148 — intercity
- 400-series highways (freeways)
- Hwy 500-699 — secondary highways
- Hwy 800-813 — tertiary highways
- 7000-series — resource & industrial roads
Prince Edward Island
Provincial highways are divided into three series'.
- Route 1-4 — primary highways
- Route 4-25 — secondary highways
- Local highways are numbered by county
- Route 101-199 — Prince County
- Route 201-299 — Queens County
- Route 301-399 — Kings County
Provincial highways are divided into three classes. Odd numbers refer to routes that are generally perpendicular to the Saint Lawrence River. Even numbers refer to routes that are generally parallel to the Saint Lawrence River.
- Autoroutes - expressways
- Route numbers for bypasses and spurs take on a prefix (4nn-9nn)
- 100-series — primary highways
- Secondary routes
- 200-series — south of the Saint Lawrence River
- 300-series — north of the Saint Lawrence River
Provincial highways are divided into three seres', and sub-series'.
- Hwy 1-99 — primary highways
- Hwy 100-399 — secondary highways which are spurs of primary highways
- Hwy 102-167 — northern routes
- Hwy 201-271 — routes to recreational areas
- Hwy 301-397 — routes to minor communities
- Hwy 600-799, 900-999 — minor highways
- Hwy 600-699 — south-north highways
- Hwy 700-799 — west-east highways
- Hwy 900-999 — northern or isolated roads
There are currently eleven territorial highways in the Northwest Territories. All eleven are named, eight are numbered 1-8, and two are winter roads.
There are a number of roads and highways in Nunavut, none are yet numbered.
There are currently fourteen territorial highways in Yukon. All fourteen are named and numbered 1-11, 14-15, & 37.
- Highways or Routes are numbered 1-10; there is no Route 6 (it is a proposed route)
- Routes are also given names (e.g. Tolo Highway)
Route numbering in Malaysia is fairly simple.
- All expressways (classified as an expressway by the Malaysian government) has a route number beginning with 'E', followed by a number. (e.g. North–South Expressway Northern Route and New Klang Valley Expressway)
- 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.
- 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.
- 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.
- All federal roads in Labuan have a three-digit number beginning with '7'.
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.
National Routes and National Highways
The Australian National Route Numbering System was introduced in 1955 along roads of national importance. The route markers have black numbers on white shields.
In the 1970s the National Highway scheme was introduced, to link capital cities, and some major regional centres. Though no longer defined in legislation, the National Highways remained signposted as such.
State Route System
Important urban and inter-regional routes not covered by the National Highway or National Route systems were marked under the State Route system. They are recognised by white numbers on blue shield markers. They were practically adopted in all states by the end of the 1980s. In some states, some less important National Routes had been downgraded to State Routes.
Alphanumeric Route Numbering System
In the late 1970s Tasmania introduced an alphanumeric system, that includes a letter signifying the quality and importance of the road. Most other states and territories have since adopted the system, either partially or completely replacing the previous systems; however there are no plans to introduce it in Western Australia.
Primary highways; called motorways in publications. These are typically dual carriageway freeway standard highways. They connect capital cities to each other or to bigger rural cities and are also applicable to major city freeways. Interchanges may either be graded or level. They carry high volumes of traffic and bypass settlements, towns and sometimes cities. The term motorway was used as more politically acceptable than tollway when some previously designated freeways were given tollbooths.
Single carriageway interstate or interregional primary highways. Traffic volume less than "M" routes but with ample overtaking lanes, sealed shoulders and markings. They may pass through or bypass town centres.
Secondary highways linking together major towns on different "A" routes including certain lesser important former national routes. In addition, they may include major bypassed sections of former "A" or "M" routes and significant tourist routes. They are reasonably good quality sealed roads with shoulders either sealed or not.
Roads linking smaller settlements and towns to "A", "B" or "M" routes. May also be applied to short bypassed sections of former "A" routes. Fully sealed surface but of moderate to poor quality and may or may not have shoulders.
Metropolitan Route Numbering System
In the 1990s in Sydney and Brisbane, urban route numbering system were streamlined in the new Metroad scheme. They are recognised by distinctive hexagonal shields and superseded the state route, freeway and National Route schemes along their path. Metroads radiate in a spoke pattern from city centres to highways outside metropolitan limits. In addition, Metroads also cover major city ring roads. Metroads are made of urban highways, main roads and urban freeways.
Non-Metroads retain the earlier state route system.
In Germany a normal route number consists of the letter A and a number:
- 1-digit-numbers are the most important autobahns
- 2- and 3-digit numbers are for connectors of 1-digit-number-autobahns
- north-south-routes numbers have odd numbers, east-west-routes have even numbers
A Bundesstraße are national highways, their numbers consists of the letter B and a number:
- 1-digit-numbers are more important than 2- or 3-digit-numbers
- north-south-routes numbers have even numbers, east-west-routes have odd numbers
- short branches of Bundesstraßen are signed with an a (e.g. B 27a)
- rerouted Bundesstraßen most time are getting an n (e.g. B 7n)
West-Berlin once had its own Bundesstraßen with letters. (see gallery)
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)).
- Road designation or abbreviation
- Highway shield
- Highway location marker
- Driver location signs
- Asian Highway Network
- Auxiliary route (United States)
- China road numbering
- International E-road network (Europe)
- State-numbered route (countries that are divided into states)
- Numbered street