Super two

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I-93 in Franconia Notch, New Hampshire, as a super two roadbed

A super two, super two-lane highway or wide two-lane, in the United States, is a two-lane surface road built to highway standards. To clarify, this means the road has the wider lanes and other safety features seen on a freeway with more lanes, typically including partial control of access, occasional passing lanes and hard shoulders. It is often built for eventual conversion to freeway or at least divided highway status once traffic volumes rise. It has also been used in cases where environmental concerns are prevalent, such as where Interstate 93 becomes a super two in Franconia Notch, New Hampshire.

Wide two-lane[edit]

In Ireland, the term wide two-lane is used by the National Roads Authority in the planning of routes using such a road type.[1] In policy documents, the designation WS2 is used.[2] WS2 is also the term 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 Republic generally have hard shoulders and are undivided single carriageway. Grade separation of junctions has been used on some schemes—for example the N20 bypassing Croom. Most wide two lane roads are wide enough that one can overtake without crossing the center line, if a vehicle in front pulls into the hard shoulder (the carriageway including hard shoulders is 15–17 metres wide[3]).

Many future national road schemes in the Republic will use 2+1 roads or 2+2 roads,[1] as opposed to wide two lane, which is considered to better suit lower capacities than that catered for by 2+1.[4] Wide two lane, if finished to particularly high quality, with grade separated interchanges, has been shown to lead to a false sense of security (from the apparently high speed road) and more dangerous driving (due to the carriageways not being 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]

See also[edit]


  1. ^ a b "National Roads Authority] - [ Major National Road Schemes in Planning". Archived from the original on 5 December 2006. Retrieved 25 April 2018. External link in |title= (help)
  2. ^ Definition of the WS2 designation by the NRA: Interim Advice Note on Road Link Design for 2+1 roads Archived 2007-10-05 at the Wayback Machine (PDF 4.7MB), page 0/2.
  3. ^ National Roads Authority: Interim Advice Note on Road Link Design for 2+1 roads, page 1/1.
  4. ^ National Roads Authority: Interim Advice Note on Road Link Design for 2+1 roads, page 9/1.
  5. ^ National Roads Authority: Interim Advice Note on Road Link Design for 2+1 roads, page 7/11.
  6. ^ "Roadway Design Manual: Super 2 Highways". Archived from the original on 11 September 2016. Retrieved 25 April 2018.