View source for One-way pair

{{Short description|Two separate corridors in opposite directions}}
{{more citations needed|date=December 2015}}
A '''one-way pair''', '''one-way couple''', or '''couplet''' refers to that portion of a bi-directional traffic facility{{spaced ndash}}such as a [[road]], [[bus]], [[streetcar]], or [[light rail]] line{{spaced ndash}}where its opposing flows exist as two independent and roughly parallel facilities.

==Description==
In the context of roads, a one-way pair consists of two [[one-way traffic|one-way streets]] whose flows combine on one or both ends into a single [[two-way street]]. The one-way streets may be separated by just a single block, such as in a [[grid plan|grid network]], or may be spaced further apart with intermediate parallel roads. 

One use of a one-way pair is to increase the vehicular capacity of a major route through a developed area such as a [[central business district]]. If not carefully treated with other traffic calming features, the benefit in vehicular capacity is offset by a potential for increased road user deaths, in particular people walking and biking.<ref>{{cite news|url=https://citylimits.org/2015/12/22/to-stop-pedestrian-deaths-we-have-to-change-the-way-we-build-our-streets|title=To Stop Pedestrian Deaths NYC Must Change How it Builds Streets}}</ref> A one-way pair can be created by converting segments of two-way streets into one-way streets, which allows lanes to be added without widening.{{citation needed span|text=It also allows easier creation of a [[green wave]] by adjusting [[traffic light]]s on the through route, because strict left turn phases are no longer required at each intersection.|date=June 2017}}

On occasion, "couplet" has been applied specifically to the point where the one-way streets and the two-way street meet, rather than the paired one-way streets themselves.<ref name=intrs89>{{cite news|url=https://news.google.com/newspapers?id=29ctAAAAIBAJ&sjid=v9AFAAAAIBAJ&pg=5004%2C878655|newspaper=Idahonian|location=Moscow|last=McCann|first=Sheila R. |title=Interest stirs again for long-delayed interchange on U.S. 95|date=June 23, 1989|page=1A}}</ref>

Flows on a one-way pair may follow the [[Right- and left-hand traffic|traffic handedness convention]] of the locale, or may be switched. Following the convention allows a one-way pair to be more easily integrated into an existing network of two-way streets, as a single two-way street is effectively split into the two sides of the pair, as in the diagram below:

{|table border=0 cellspacing=0
! (rejoin) || (one-way pair) || (split)
|-
| ||/ ← ← ← ← ← ← ← /|| 
|-
| ← ← ← ||/ ← ← ← ← ← ← ← /|| ← ← ←
|-
| → → → ||/ → → → → → → → /|| → → →
|-
| ||/ → → → → → → → /|| 
|}

==Criticism==
International research has found that there are several disadvantages to one-way pairs including:<ref name="LetterRePCTCResolution2010">{{cite letter
|url=https://meetings.cityofsydney.nsw.gov.au/Data/Council/20100621/Agenda/rec_2242771.pdf#page=2
|title=Information Relevant To Item 9.2 - Newtown Erskineville Camperdown and Darlington Pedestrian Cycling Traffic Calming Plan at the Planning Development and Transport Committee. 
|author1=Elizabeth Rush, Senior Transport Planner 
|author2=Andrew Thomas, Acting Director City Strategy and Design
|recipient=Lord Mayor and Councillors
|ref=S063088
|date=2010-06-16
|publisher=City of Sydney
|archive-url=https://web.archive.org/web/20190405070757/https://meetings.cityofsydney.nsw.gov.au/Data/Council/20100621/Agenda/rec_2242771.pdf
|archive-date=2019-04-05
|url-status=live
|access-date=2025-11-07
|page=2
}}</ref>

* they can lead to road users taking less care and travelling at increased speeds because of the expectation that they will not encounter opposing traffic<ref>{{cite conference
|url=https://onlinepubs.trb.org/Onlinepubs/sr/sr93/93-004.pdf
|title=One-Way Major Arterial Streets
|author=John A. Bruce
|conference=Improved Street Utilization Though Traffic Engineering
|date=1967-05-22
|location=Washington, D.C.
|publisher=National Research Council (U.S.) Highway Research Board
|archive-url=https://web.archive.org/web/20240410234448/https://onlinepubs.trb.org/Onlinepubs/sr/sr93/93-004.pdf
|archive-date=2024-04-10
|url-status=live
}}</ref>
* they do not reduce traffic, it is simply transferred to other streets<ref>{{cite web
|url=https://www.design.upenn.edu/sites/default/files/Glatting_One%20Way%20Streets.pdf#page=2
|page=1
|author1=Jackson Glatting
|author2=Anglin Kercher
|title=Advantages and Disadvantages of One‐Way Streets
|date=2007-10-30
}}</ref><ref name="StranglingOurselves2001"/>
* they are likely to increase travel distances for residents<ref>{{cite web
|title=Safety of One-Way Urban Streets
|author=I. Hocherman, A. S. Hakkert, and]. Bar-Ziv
|url=https://onlinepubs.trb.org/Onlinepubs/trr/1990/1270/1270-003.pdf
|date=1990
|location=Washington, D.C.
|publisher=Transportation Research Record
}}</ref><ref name="StranglingOurselves2001">{{cite journal
|url=https://onlinepubs.trb.org/onlinepubs/circulars/ec019/Ec019_f2.pdf
|title=Downtown Streets: Are We Strangling Ourselves on One-Way Networks?
|author1=G. Wade Walker
|author2=Walter M. Kulash
|author3=Brian T. McHugh
|date=2001
|journal=Transportation Research E-Circular
|volume=E-C019
|publisher=Transportation Research Board
|archive-url=http://web.archive.org/web/20250614131703/https://onlinepubs.trb.org/onlinepubs/circulars/ec019/ec019_f2.pdf
|archive-date=2025-06-14
|url-status=live
}}</ref>{{rp|9}}

The [[American Association of State Highway and Transportation Officials]] suggests converting two-way to one-way operation in situations where an urban street has too many pedestrian-vehicle conflicts.<ref>{{cite book |title=A Policy on Geometric Design of Highways and Streets
|author=AASHTO
|date=2011
|location=Washington, D.C.
|publisher=American Association of State Highway and Transportation Officials
}}</ref><ref>{{cite web
|url=https://www.transportist.net/p/elements-of-access-one-way-streets
|title=Elements of Access: One-Way Streets
|author=Wes Marshall
|date=2015-05-11
|publisher=Transportist
}}</ref>

One-way streets benefit drivers, but two-way streets benefit everyone else. They can improve air quality, safety for cyclists and pedestrians, and promote patronage of local businesses.<ref>{{cite web
|url=https://transfersmagazine.org/magazine-article/issue-11/rethinking-the-one-way-street/
|title=Rethinking the One-Way Street
|date=August 2023
|author1=Geoff Boeing
|author2=William Riggs
|publisher=Transfers Magazine
}}</ref><ref>{{cite journal
|url=https://journals.sagepub.com/doi/10.1177/0739456X221106334
|title=Converting one-way streets to two-way streets to improve transportation network efficiency and reduce vehicle distance traveled
|author1=Geoff Boeing
|author2=William Riggs
|date=2022
|journal=Journal of Planning Education and Research
|volume=44
|issue=3
|doi=10.1177/0739456X221106334
|url-access=subscription
}}</ref>

==Examples==
===Australia===
The [[Sydney central business district]] features a number of one way pairs. One example is [[Pitt Street]] with [[Castlereagh Street]]. Pitt street carries only northbound traffic from [[Goulburn Street]] to [[Market Street, Sydney|Market Street]]. Castlreagh Street only carries southbound traffic on its entire length from [[Hunter Street, Sydney|Hunter Street]] to [[Hay Street, Sydney|Hay Street]]. [[Trams in Sydney|Trams]] once ran from [[Central railway station, Sydney|Central station]] to [[Circular Quay]] along Pitt Street and back to Central station along Castlereigh, Bligh, Bent and Loftus Streets. Other examples are [[York Street, Sydney|York]] and [[Clarence Street, Sydney|Clarence]] Streets between the [[Sydney Harbour Bridge|Harbour Bridge]] and [[Sydney Town Hall|Town Hall]], and [[King Street, Sydney|King]] and [[Market Street, Sydney|Market]] Streets between [[Sussex Street, Sydney|Sussex]] and [[Elizabeth Street, Sydney|Elizabeth]] Streets.

In [[Redfern, New South Wales|Redfern]], [[Elizabeth Street, Sydney|Elizabeth Street]] is paired with [[Chalmers Street]] between Redfern Street and [[Eddy Avenue]]. Prior to the opening of the [[Eastern Distributor]] in 1999, Bourke and [[Crown Street, Sydney|Crown]] Streets were paired between [[Woolloomooloo]] and [[Waterloo, New South Wales|Waterloo]] after which they were converted back to two-way streets. The paired roads from the [[Anzac Bridge]] through [[Ultimo, New South Wales|Ultimo]], [[Chippendale, New South Wales|Chippendale]], [[Redfern, New South Wales|Redfern]] to [[Waterloo, New South Wales|Waterloo]] is known as the [[Southern Arterial Route]].

In the [[Brisbane central business district]], [[Ann Street, Brisbane|Ann Street]] is paired with [[Turbot Street]] and [[George Street, Brisbane|George Street]] with North Quay, the latter by the [[Brisbane River]]. In [[South Bank, Queensland|Southbank]], Merivale Street is paired with Cordelia Street from Montague Road to Vulture Street. In [[East Brisbane]], [[Vulture Street, Brisbane|Vulture Street]] is paired with [[Stanley Street, Brisbane|Stanley Street]].

In the [[Hobart central business district]] a couplet of [[Davey Street]] and [[Macquarie Street, Hobart|Macquarie Street]] traverse the length of the city centre. The [[Tasman Highway]] joins the pair at the northeastern end at an interchange with the [[Brooker Highway]]. This current alignment was implemented in 1987 to coincide with the completion of the [[Hotel Grand Chancellor, Hobart|Sheraton Hotel]]. It was originally intended that the couplet system would serve as a stop gap measure prior to the construction of a freeway in [[Hobart Area Transportation Study|Hobart's Transportation study of 1965]]. Prior to this, all traffic in Hobart was two-way.

===Canada===
[[Alberta Highway 2]] is a one-way pair in southern [[Edmonton]] on [[Calgary Trail & Gateway Boulevard|Calgary Trail and Gateway Boulevard]] between 31 Avenue NW and [[Whitemud Drive]]. Alberta Highway 2 is also one-way pair through the towns of [[Fort Macleod]] (23 and 25 Streets; [[Concurrency (road)|cosigned]] with [[Alberta Highway 3]]) and [[Nanton, Alberta|Nanton]] (20 and 21 Avenues). [[Alberta Highway 16]] ([[Yellowhead Highway]]) is a one-way pair through the town of [[Edson, Alberta|Edson]] (2nd & 4th Avenues).

[[British Columbia Highway 99]] is a one-way pair in downtown [[Vancouver]] on Seymour and Howe Streets between the [[Granville Street Bridge]] and [[Georgia Street]]. [[British Columbia Highway 97]] is a one-way pair through the community of [[Westbank, British Columbia|Westbank]] in [[West Kelowna]], following Main Street and Dobbin Road.

[[Saskatchewan Highway 1]] ([[Trans-Canada Highway]]) splits into a functional one-way pair for {{Convert|15|km|mi|0|abbr=on}} between [[Uren, Saskatchewan|Uren]] and [[Ernfold]], with the entire village of Ernfold being located between the eastbound and westbound lanes.

===Japan===
[[Japan National Route 340]] travels through the central part of [[Hachinohe]] in [[Aomori Prefecture]] as a one-way pair between its northern terminus at an intersection with [[Japan National Route 45]] and Aomori Prefecture Route 251.

===United States===
[[Interstate 78]] travels along a one-way pair of surface streets, [[New Jersey Route 139#I-78 concurrency|12th Street and 14th Street]], in [[Jersey City, New Jersey]], between the end of the [[New Jersey Turnpike]] Newark Bay Extension and the [[Holland Tunnel]], which leads into [[New York City]], [[New York (state)|New York]].

There are hundreds of one-way pairs among the streets and avenues of New York City. One example is [[Fifth Avenue]] with [[Madison Avenue]]. Others include [[First Avenue (Manhattan)|First Avenue]] with [[Second Avenue (Manhattan)|Second Avenue]]; [[Third Avenue]] with [[Lexington Avenue]]; and [[Seventh Avenue (Manhattan)|Seventh Avenue]] with either [[Sixth Avenue (Manhattan)|Sixth Avenue]] or [[Eighth Avenue (Manhattan)|Eighth Avenue]].

Two major streets in the city of [[Pittsburgh]] serve as a one-way pair; [[Forbes Avenue]] and [[Fifth Avenue (Pittsburgh)|Fifth Avenue]]. Both streets begin in [[Downtown Pittsburgh|Downtown]] near [[Point State Park]] before becoming a one-way pair just east of [[Market Square (Pittsburgh)|Market Square]], with Forbes serving outbound traffic and Fifth serving inbound traffic, going through [[Uptown Pittsburgh|Uptown]] and [[Oakland (Pittsburgh)|Oakland]] before both streets end up with two-way traffic and diverge, with Fifth Avenue eventually terminating in [[Highland Park (Pittsburgh)|Highland Park]], while Forbes terminates in [[Wilkinsburg, Pennsylvania|Wilkinsburg]] just outside the city limits. The mostly two-way [[Boulevard of the Allies]] parallels Forbes and Fifth for most of the time the two streets are a one-way pair.

The east side of [[Portland, Oregon]], features a number of one-way pairs, both north–south and east–west, with the east–west pairs being associated with bridges; these all follow the usual flow convention – see [[Transportation in Portland, Oregon#Traffic flow|Transportation in Portland, Oregon]], for more details. By contrast, the [[Portland Transit Mall]], which is a public transportation (bus and rail) corridor, has the opposite flow, with the westernmost component (6th Avenue) running north, with the eastern component (5th Avenue) running south.

There are a number of one-way pairs in [[Downtown Los Angeles]], [[California]].  These include [[3rd Street, Los Angeles|3rd]] and [[4th Street, Los Angeles|4th]] streets, [[5th Street, Los Angeles|5th]] and [[6th Street, Los Angeles|6th]] streets, [[8th Street, Los Angeles|8th]] and [[9th Street, Los Angeles|9th]] streets, [[11th Street, Los Angeles|11th]] and [[12th Street, Los Angeles|12th]] streets, and [[Main Street (Los Angeles)|Main]] and [[Spring Street (Los Angeles)|Spring]] streets.

Levick Street and Robbins Street in [[Philadelphia]] are considered a one-way pair. The streets carry traffic to and from the [[Tacony-Palmyra Bridge]] through the [[Mayfair, Philadelphia|Mayfair]] and [[Wissinoming, Philadelphia|Wissinoming]] neighborhoods. Between Frankford Avenue and [[Roosevelt Boulevard (Philadelphia)|Roosevelt Boulevard]], the streets carry [[U.S. Route 13 in Pennsylvania|US 13]] in their respective direction.

In [[Orlando, Florida|Orlando]], [[Florida]], Princeton Street carries 4 miles of SR-438 near [[Interstate 4]]. Over a portion of that, Smith Street carries the westbound traffic. At Lake Lawsona, Mills Avenue splits into Jackson Street northbound and Thornton Avenue southbound.

In Virginia Beach, Virginia, the eastern end of Interstate 264 transitions to 21st and 22nd Street, each going in its respective direction.<ref>{{cite web |url=http://www.roadstothefuture.com/I264_VA_Desc.html |title=Interstate 264 in Virginia |publisher=Roadstothefuture.com |date= |access-date=2022-03-20}}</ref>

==See also==
{{portal|Roads}}
*[[Directional running]], the equivalent for [[rail transport]]

==References==
{{Reflist}}

[[Category:Types of roads]]