Two-lane expressway

Justification

Two-lane freeways are usually built as a temporary solution due to lack of funds, as an environmental compromise or as a way to overcome problems constrained from highway reconstruction when there are four lanes or more. If the road is widened, the existing road is typically allocated to traffic going in one direction, and the lanes for the other direction are built as a whole new roadbed adjacent to the existing one. When upgraded in this manner, the road becomes a typical freeway. Many two-lane freeways are built so that when the road is upgraded to a proper divided freeway, the existing overpasses and ramps do not need reconstruction.

Super 2

A super-2 expressway is a high-speed surface road with at-grade intersections, depending on the common usage of the term expressway in the area. By this definition, Super-2s can be considered the first stage of project which is expected to become a full freeway, with the transportation authority owning the land necessary for the future adjacent carriageway. At-grade intersections exist but there is sufficient land to replace them with interchanges. In some US states, a super-2 expressway is simply referred to as a super-2, regardless of whether it is fully controlled-access or not. Highway 410 in Ontario was originally a super-2 before being upgraded to a full freeway. Similarly, most of Highway 102 in Nova Scotia was a super-2 for three decades before being upgraded. Many super-2 expressways are simply just short transitional segments between surface street and four-lane divided freeways.

Ireland

In the Republic of Ireland, the term wide two-lane is used by the National Roads Authority. In policy documents, the designation WS2 is used, which is also used in the UK for a wide single carriageway. 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). Many future Irish road schemes will use 2+1 roads or 2+2 roads,

Texas

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. Chisholm Trail Parkway is a Super 2 located south of Fort Worth in the southern segment of the route, though there are future plans to extend the lanes to 2 lanes on each side.

Ontario

The Southwest Bypass of Sudbury, in the Province of 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. 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.

Nova Scotia

In the Province of Nova Scotia the parts of Highway 101, Highway 103, and Highway 104 that are not already four-lane, controlled access, highways employ a Super 2 configuration. As funding becomes available, the Super 2 portions of the highways are being twinned.

Quebec

In the Province of Quebec, part of Autoroute 50, between Buckingham and Lachute is built as a Super 2. As funding becomes available, the Super 2 portions of the highways are being twinned. In addition, Autoroute 55 south of Bécancour employs a Super 2 format.

References

References

1. (2019). "Express road". [[Publications Office of the European Union]].
2. "Express road". United Nations Economic and Social Commission for Western Asia.
3. ["National Roads Authority] - http://www.nra.ie/RoadSchemeActivity/MajorRoadSchemesinPlanning/ Major National Road Schemes in Planning".
4. Definition of the WS2 designation by the NRA: [http://www.nra.ie/Publications/DownloadableDocumentation/RoadDesignConstruction/file,3620,en.pdf Interim Advice Note on Road Link Design for 2+1 roads] {{webarchive. link. (2007-10-05 ([[PDF]] 4.7MB), page 0/2.)
5. National Roads Authority: Interim Advice Note on Road Link Design for 2+1 roads, page 1/1.
6. as opposed to wide two-lane, which may better suit lower capacities than does 2+1.National Roads Authority: Interim Advice Note on Road Link Design for 2+1 roads, page 9/1.
7. "Roadway Design Manual: Super 2 Highways".
8. "Sudbury to Greater Sudbury".
9. (Mar 12, 2009). "Preferred Plan".
10. (14 July 2016). "Highway Twinning Public Consultations".
11. (13 July 2025). "Autoroute 50 twinning in Argenteuil to begin this year".