The examples and perspective in this article deal primarily with Ireland, Texas, and Ontario and do not represent a worldwide view of the subject.(February 2024) |
A super two, super two-lane highway or wide two-lane is a two-lane surface road built to highway standards with wide lanes and other safety features normally present on a freeway with more lanes, typically including occasional passing lanes and hard shoulders. It is often built for eventual conversion to divided highway status once traffic volumes rise.
In the Republic of Ireland, the term wide two-lane is used by the National Roads Authority. [1] In policy documents, the designation WS2 is used, [2] which is also used in the UK for a wide single carriageway.
Wide two-lane roads are common on national roads, both on less important but medium-capacity routes, and on more important routes not yet upgraded to dual carriageway or motorway. Wide two-lane roads in the Irish Republic generally have hard shoulders and are undivided single carriageway. Grade separation of junctions has been used in some instances—for example, the N20 bypassing Croom. Most wide two-lane roads are wide enough that a vehicle may overtake another without crossing the center line if the vehicle in front pulls into the hard shoulder (the carriageway including hard shoulders is 15–17 meters wide [3] ).
Many future Irish road schemes will use 2+1 roads or 2+2 roads, [1] as opposed to wide two-lane, which may better suit lower capacities than does 2+1. [4] Wide two-lane, if finished to high quality with grade separated interchanges, has been shown to lead drivers into a false sense of security (from the apparently high speed road) and more dangerous driving (because the carriageways are not separated). [5]
In Texas, a two-lane highway that has an alternating passing lane is called a Super 2, but it is actually a 2+1 road. [6]
The Southwest Bypass of Sudbury, Ontario is currently at Super 2 standards. There is one interchange and four at-grade, unsignalized intersections along an 11.3 km stretch of 2-lane highway; between being divided at interchanges on either end. [7] While plans have existed since the 1967 "Planning Study for the Sudbury Southwest By-Pass", there is currently not funding in place to twin the bypass to a full 4-lane expressway. [8]
The M1 motorway connects London to Leeds, where it joins the A1(M) near Aberford, to connect to Newcastle. It was the first inter-urban motorway to be completed in the UK; the first motorway in the country was the Preston Bypass, which later became part of the M6.
The A21 is a trunk road in Southern England, one of several which connect London and various commuter towns to the south coast. It provides a link to Hastings, East Sussex and parts of Kent. Half of the distance covered is over gently undulating terrain, with some hills and bends. Often traffic is slow-moving, particularly on weekdays on the short single carriageway stretches; and in summer with holiday traffic. Because of this, people have described the A21 as "a joke" and businesspeople have been reported to "hate coming down the A21". There have been many proposals to upgrade parts of the A21 in response to this.
A shoulder, hard shoulder (British) or breakdown lane is an emergency stopping lane by the verge on the outer side of a road or motorway. Many wider freeways, or expressways elsewhere have shoulders on both sides of each directional carriageway — in the median, as well as at the outer edges of the road, for additional safety. Shoulders are not intended for use by through traffic, although there are exceptions.
The N4 road is a national primary road in Ireland, running from Dublin to the northwest of Ireland and Sligo town. The M6 to Galway diverges from this route after Kinnegad, while the N5 to Westport diverges at Longford town. Most sections of the N4 that are motorway-standard are designated the M4 motorway.
A dual carriageway (BrE) or a divided highway (AmE) is a class of highway with carriageways for traffic travelling in opposite directions separated by a central reservation (BrE) or median (AmE). Roads with two or more carriageways which are designed to higher standards with controlled access are generally classed as motorways, freeways, etc., rather than dual carriageways.
King's Highway 17, more commonly known as Highway 17, is a provincially maintained highway and the primary route of the Trans-Canada Highway through the Canadian province of Ontario. It begins at the Manitoba boundary, 50 km (31 mi) west of Kenora, and the main section ends where Highway 417 begins just west of Arnprior. A small disconnected signed section of the highway still remains within the Ottawa Region between County Road 29 and Grants Side Road. This makes it Ontario's longest highway.
The N5 road is a national primary road in Ireland, connecting Longford town with Westport. It is the main access route from Dublin to most of County Mayo, including the county's largest towns, Castlebar, Ballina, and Westport.
The road hierarchy categorizes roads according to their functions and capacities. While sources differ on the exact nomenclature, the basic hierarchy comprises freeways, arterials, collectors, and local roads. Generally, the functional hierarchy can more or less correspond to the hierarchy of roads by their owner or administrator.
The N17 road is a national primary road in Ireland, and is part of the Atlantic Corridor route. It begins in County Galway and ends in County Sligo. On 27 September 2017 the southern, Tuam–Galway, section was upgraded to motorway status and designated M17.
The N20 road is a national primary road in Ireland, connecting the cities of Cork and Limerick. Buttevant, Croom, Charleville, Mallow and Blarney are major towns along the route. A short section of the route is motorway standard and is designated as the M20 Motorway.
The N52 road is a national secondary road in Ireland. It links the M7 motorway from just south of Nenagh, County Tipperary to the M1 motorway north of Dundalk in County Louth. The route forms a connection between the north east of Ireland and the mid west traversing the midlands. It interchanges with the M6 at Kilbeggan and at Tyrrellspass, the N4 at Mullingar, the N3 at Kells, and the N2 at Ardee before continuing towards Dundalk.
The N25 road is a national primary road in Ireland, forming the route from Cork to Rosslare Europort via Waterford City. The road is part of the E30 European route and a short section is also part of the E01 European route. It forms part of the proposed Atlantic Corridor route.
2+1 road is a specific category of three-lane road, consisting of two lanes in one direction and one lane in the other, alternating every few kilometres, and usually separated with a steel cable barrier. The second lane allows faster-moving traffic to overtake slower vehicles at regular intervals. Traditional roads of at least 10 metres (33 ft) width can be converted to 2+1 roads and reach near-motorway safety levels at a much lower cost than an actual conversion to motorway or dual carriageway.
The A494 is a trunk road in Wales and England. The route, which is officially known as the Dolgellau to South of Birkenhead Trunk Road, runs between the terminus of the M56 motorway between Mollington and Capenhurst and the A470 at Dolgellau, Gwynedd. Its northern sections remain among the busiest roads in Wales.
The R136 road is a regional road in Ireland, located in the southwest of Dublin. Named the Outer Ring Road, the route, which is dual carriageway, runs from the N4 at Lucan to the N81 at Tallaght, bypassing west of Clondalkin and crossing the N7 near Citywest. It was built as part of the planning for the new town of Adamstown.
A two-lane expressway or two-lane freeway is an expressway or freeway with only one lane in each direction, and usually no median barrier. It may be built that way because of constraints, or may be intended for expansion once traffic volumes rise. The term super two is often used by roadgeeks for this type of road, but traffic engineers use that term for a high-quality surface road. Most of these roads are not tolled.
A High-quality dual carriageway (HQDC) is a road category in Ireland. It is defined as an all-purpose dual carriageway road type built to near motorway standards, but without motorway classification or motorway restrictions. High-quality dual carriageways have full grade-separated access and do not have junctions with minor roads. Such roads in the Republic of Ireland have been built as part of the 2000–2006 and 2007–2013 National Development Plans, including interurban routes from Dublin to other cities.
The M8 motorway is an inter-urban motorway in Ireland, which forms part of the motorway from the capital Dublin to Cork city. The 149 km motorway commences in the townland of Aghaboe, County Laois and runs through the counties of Kilkenny, Tipperary and Limerick, terminating at the Dunkettle interchange in Cork City. First called for in the Road Needs Study (1998), it was later incorporated into the National Development Plan (2000–2006) and later still formed part of the Irish Government's Transport 21 plan for infrastructural development. The majority of the M8 (115 km) was built between 2006 and 2010. On 28 May 2010, the motorway was completed and had replaced almost all of the single-carriageway N8 except for a short section of urban road in Cork City.
In Ireland, the highest category of road is a motorway, indicated by the prefix M followed by a one- or two-digit number. The motorway network consists entirely of motorway-grade dual carriageways and is largely focused upon Dublin. There are also several three-lane motorways, while Ireland's busiest road, the M50, incorporates four-lane, five-lane, and six-lane stretches.
This article describes the highway systems available in selected countries.
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