Aring road (also known ascircular road,beltline,beltway,circumferential (high)way,loop ororbital) is a road or a series of connected roads encircling a town, city or country. The most common purpose of a ring road is to assist in reducing traffic volumes in the urban centre, such as by offering an alternate route around the city for drivers who do not need to stop in the city core. Ring roads can also serve to connect suburbs to each other, allowing efficient travel between them.
In Europe and Australia, some ring roads, particularly longer ones ofmotorway standard, are known as "orbital motorways". Examples are theLondon Orbital (generally known as the M25; 188 km),Sydney Orbital Network (110 km) andRome Orbital (68 km).
In the United States many ring roads are calledbeltlines,beltways orloops, such as theCapital Beltway aroundWashington, D.C. Some ring roads, such as Washington's Capital Beltway, use "Inner Loop" and "Outer Loop"terminology for directions of travel, sincecardinal (compass) directions cannot be signed uniformly around the entire loop. The term 'ring road' is occasionally – and inaccurately – used interchangeably with the term 'bypass'.
TheSydney Orbital Network, New South Wales, AustraliaTheAutostrada A58, theMilan external east ring road, Italy. Together with theAutostrada A50 (Milan west ring road), theAutostrada A51 (Milan east ring road) and theAutostrada A52 (Milan north ring road), it is the largest system of ring roads around a city in Italy, for a total length greater than 100 kilometres (62 mi).[1]
Bypasses around many large and small towns were built in many areas when many old roads were converted to four-lane status in the 1930s to 1950s, such as those along theOld National Road (now generallyU.S. 40 orInterstate 70) in the United States, leaving the old road in place to serve the town or city, but allowing through travelers to continue on a wider, faster and safer route.
Construction of fully circumferential ring roads has generally occurred more recently, beginning in the 1960s in many areas, when the U.S.Interstate Highway System and similar-quality roads elsewhere were designed. Ring roads have now been built around numerous cities and metropolitan areas, including cities with multiple ring roads, irregularly shaped ring roads and ring roads made up of various other long-distance roads.
London has three ring roads (theM25 motorway, theNorth andSouth Circular roads and theInner Ring Road).Birmingham also has three ring roads which consist of theBirmingham Box; theA4540, commonly known as the Middleway; and theA4040, the Outer Ring Road. Birmingham once had a fourth ring road, theA4400. This has been partially demolished and downgraded to improve traffic flow into the city. Other British cities have two:Leeds,Sheffield,Norwich andGlasgow.Cleveland, OH andSan Antonio, TX, in theUnited States, also each have two, whileHouston, Texas will have three official ring roads (not including the downtown freeway loop). Some cities have far more – Beijing, for example, hassix ring roads, simply numbered in increasing order from the city center (though skipping #1), while Moscow has five, three innermost (Central Squares of Moscow,Boulevard Ring andGarden Ring) corresponding to the concentric lines of fortifications around the ancient city, and the two outermost (MKAD andThird Ring) built in the twentieth century, though, confusingly, the Third Ring was built last.
Geographical constraints can complicate the construction of a complete ring road. For example, theBaltimore Beltway inMaryland formerly crossedBaltimore Harbor on a high archbridge prior to its collapse in 2024, and much of the partially completedStockholm Ring Road inSweden runs through tunnels or over long bridges. Some towns or cities on sea coasts or near rugged mountains cannot have a full ring road. Examples of such partial ring roads are Dublin'sring road; and, in the US,Interstate 287, mostly inNew Jersey (bypassing New York City), andInterstate 495 aroundBoston, none of which completely circles these seaport cities.
In other cases, adjacent international boundaries may prevent ring road completion. Construction of a true ring road aroundDetroit is effectively blocked by its location on the border with Canada and theDetroit River; although constructing a route mostly or entirely outside city limits is technically feasible, a true ring around Detroit would necessarily pass through Canada, and soInterstate 275 andInterstate 696 together bypass but do not encircle the city. Sometimes, the presence of significant natural or historical areas limits route options, as for the long-proposedOuter Beltway around Washington, D.C., where options for a new westernPotomac River crossing are limited by a nearly continuous corridor of heavily visited scenic, natural, and historical landscapes in thePotomac River Gorge and adjacent areas.
When referring to a road encircling a capital city, the term "beltway" can also have a political connotation, as in theAmerican term "Inside the Beltway", derivedmetonymically from theCapital Beltway encircling Washington, D.C.
Ring roads have been criticised forinducing demand, leading to more car journeys being taken and thus higher levels of pollution being created. By creating easy access by car to large areas of land, they can also act as a catalyst for development, leading tourban sprawl and car-centric planning.[2] Ring roads have also been criticised for splitting communities and being difficult to navigate for pedestrians and cyclists.[3]
TheLeeds Inner Ring Road in England was built in a series of tunnels to save space and avoid physically separating the city's centre from its suburbs.Sardar Patel Ring Road, Ahmedabad
Most orbital motorways (or beltways) are purpose-built major highways around a town or city, typically without either signals or road or railroad crossings. In the United States, beltways are commonly parts of the Interstate Highway System. Similar roads in the United Kingdom are often called "orbital motorways". Although the terms "ring road" and "orbital motorway" are sometimes used interchangeably, "ring road" often indicates a circumferential route formed from one or more existing roads within a city or town, with the standard of road being anything from an ordinary city street up to motorway level. An excellent example of this is London's North Circular/South Circular ring roads, which are largely made up of (mainly congested) ordinary city streets.
In some cases, a circumferential route is formed by the combination of a major through highway and a similar-quality loop route that extends out from the parent road, later reconnecting with the same highway. Such loops not only function as abypass for through traffic, but also to serve outlyingsuburbs. In the United States, an Interstate highway loop is usually designated by a three-digit number beginning with an even digit before the two-digit number of its parent interstate. Interstate spurs, on the other hand, generally have three-digit numbers beginning with an odd digit.
Within the United States, even numbered three digit interstate highways act a circumferential route of the two digit parent interstate. Some instances (such asInterstate 495, DC) completely circle, while some (such asInterstate 495, MA) partially loop, either due to geographical or cancelled/non-completed highways. Within cities, ring roads sometimes have local nicknames; these includeWashington DC's Interstate 495 (The "Capital Beltway"),Interstate 270 inColumbus, Ohio (The "Outerbelt"), andInterstate 285 inAtlanta (The "Perimeter").
The longest complete belt road, or a beltway that is only two lanes, in the United States isHawaii Belt Road, a 260-mile (420 km) belt inHawaii that forms a complete belt road aroundHawaii Island.[5]
Other major U.S. cities with such a beltway superhighway:
Boston—Route 128/Interstate 95 andInterstate 93/U.S. Route 1 form an inner beltway, and Interstate 495 (Massachusetts) forms an outer beltway. Inside the inner Route 128/I-95 and I-95/US 1 beltway, there were proposals (sinced canceled) for another beltway (at the time called the "Inner Belt" that would have carriedInterstate 695; I-95 would have entered Boston via theSouthwest Corridor (Since redeveloped as part of theNortheast Corridor Mile Posts 217.3-228.7), while the rest of the belt would have carried Interstate 695.
Providence, Rhode Island—Rhode Island Route 10 serves as a partial inner beltway, whileInterstate 295 serves as a partial beltway to the west of Providence. Two different proposals (both since canceled) would have completed the outer I-295 beltway; the unbuilt sections were going to be designatedInterstate 895.
Edmonton, Alberta, has two ring roads. The first is a loose conglomeration of four majorarterial roads with an average distance of 6 kilometres (3.7 mi) from the downtown core.Yellowhead Trail forms the northern section,Wayne Gretzky Drive/75 Street forms the eastern section,Whitemud Drive forms the southern and longest section, and170 Street forms the western and shortest section. Whitemud Drive is the only section that is a truecontrolled-access highway, while Yellowhead Trail and Wayne Gretzky Drive have interchanges and intersections and are therefore bothlimited-access roads. Yellowhead Trail is currently being upgraded to full freeway standards. 170 Street and 75 Street are merely large arterial roads with intersections only.[6] The second and more prominent ring road is namedAnthony Henday Drive; it circles the city at an average distance of 12 kilometres (7.5 mi) from the downtown core. It is a freeway for its entire 78-kilometre (48 mi) length, and was built to reduce inner-city traffic congestion, created a bypass of Yellowhead Trail, and has improved the movement of goods and services across Edmonton and the surrounding areas. It was completed in October 2016 as the first free-flowing orbital road in Canada.[7][8]
Stoney Trail is a ring road that circles the city ofCalgary, Alberta, for an entire length of 101-kilometre (63 mi).[9]
Regina, Saskatchewan has a partial ring road that is namedRing Road; however, due to the city's urban growth since the road was originally constructed, it no longer functions as a true ring road and has instead come to be used partially for local arterial traffic. TheRegina Bypass, a new partial ring road, has replaced it, although Ring Road must still be used in the northeast quadrant of the city.
Sudbury, Ontario, has a partial ring road consisting of theSouthwest and Southeast Bypasses segment ofHighway 17, and the Northwest Bypass segment ofHighway 144. An unofficial northeast "bypass" route can also be completed on city arterial roads that largely bypass the urban core of the city, but are not fully controlled-access and must be shared with local traffic in theNickel Centre andRayside-Balfour districts of the city.
Most major cities in Europe are served by a ring road that circles either the inner core of their metropolitan areas or the outer borders of the city proper or both. In major transit hubs, such as theÎle-de-France region surrounding Paris and theFrankfurt area, major national highways converge just outside city limits before forming one of several routes of an urban network of roads circling the city. Unlike in United States, route numbering is not a challenge on European ring roads as routes merge to form the single designated road. However, exit and road junction access can be challenging due to the complexity of other routes branching from or into the ring road.
One of the most renowned ring roads is theVienna Ring Road (Ringstraße), a grand boulevard constructed in the mid-19th century and filled with representative buildings. Due to its unique architectural beauty and history, it has also been called the "Lord of the ring roads", and is declared by UNESCO as part of Vienna'sWorld Heritage Site.[10][11]
Major European cities that are served by a ring road or ring road system:
Milan, Italy –Autostrada A4,Autostrada A50 (West),Autostrada A51 (East),Autostrada A52 (North) andAutostrada A58 (Outer Eastern) bypass roads (it is the largest system of ring roads around a city in Italy, for a total length greater than 100 kilometres (62 mi)[1]), Circolare Esterna (periphery ring road), Circonvallazione (ring road around the centre), Cerchia Interna (ring road in the city centre)
InIceland, there is a 1,332 km ring road, calledthe ring road (or Route 1), around most of the island (excluding only the remoteWestfjords). Most of the country's settlements are on or near this road.
Chiang Mai, Thailand – Chiang Mai Outer Ring Road (National Highway 121)
Christchurch, New Zealand –Christchurch Ring Road includes parts of State Highways1,74, and76. The "Four Avenues" (Bealey Avenue, Fitzgerald Avenue, Moorhouse Avenue, and Deans Avenue) serve as an inner ring around the central city.
^"Northeast Anthony Henday Drive". Alberta Transportation. 2016.Archived from the original on 12 October 2016. Retrieved2 October 2016.The northeast leg of Anthony Henday Drive opened on October 1, 2016, after five years of construction...
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