A one-way pair, one-way couple, or couplet refers to that portion of a bi-directional traffic facilitysuch as a

road A road is a linear way for the conveyance of traffic that mostly has an improved surface for use by vehicles (motorized and non-motorized) and pedestrians. Unlike streets, the main function of roads is transportation. There are many types of ...

bus A bus (contracted from omnibus, with variants multibus, motorbus, autobus, etc.) is a road vehicle that carries significantly more passengers than an average car or van. It is most commonly used in public transport, but is also in use for cha ...

streetcar A tram (called a streetcar or trolley in North America) is a rail vehicle that travels on tramway tracks on public urban streets; some include segments on segregated right-of-way. The tramlines or networks operated as public transport ...

, or light rail linewhere 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 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 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 A central business district (CBD) is the commercial and business centre of a city. It contains commercial space and offices, and in larger cities will often be described as a financial district. Geographically, it often coincides with the " cit ...

. 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. 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. 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. Flows on a one-way pair may follow the 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:

Examples

Australia

Sydney CBD features a number of one way pairs, all north-south. One example is Pitt Street with Castlereagh Street. Pitt street carries only northbound traffic from Goulbern Street to Market Street. Castlreagh Street only carries southbound traffic on its entire length from Hunter Street to Hay Street near central station. Trams once ran from Central Station to Circular Quay along Pitt Street and back to Central Station along Castlereigh, Bligh, Bent and Loftus Streets. In Redfern, part of Elizabeth Street is paired with Chalmers street. This follows the usual flow convention. In the Brisbane CBD Ann Street is paired with Turbot Street and George Street with North Quay, the latter by the

Brisbane River The Brisbane River is the longest river in South East Queensland, Australia, and flows through the city of Brisbane, before emptying into Moreton Bay on the Coral Sea. John Oxley, the first European to explore the river, named it after the G ...

. In Southbank, Merivale Street is paired with Cordelia Street from Montague Road to Vulture Street. In East Brisbane, Vulture Street is paired with

Stanley Street Stanley Street may refer to: Streets: *Stanley Street, Brisbane *Stanley Street, East Sydney *Stanley Street, Hong Kong *Stanley Street, Liverpool * Stanley Street (Montreal) * Stanley Street, Singapore In fiction: *Stanley Street, the prime setti ...

Japan

Japan National Route 340 travels through the central part of Hachinohe in

Aomori Prefecture is a prefecture of Japan in the Tōhoku region. The prefecture's capital, largest city, and namesake is the city of Aomori. Aomori is the northernmost prefecture on Japan's main island, Honshu, and is bordered by the Pacific Ocean to the ea ...

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, 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, often called New York City or NYC, is the most populous city in the United States. With a 2020 population of 8,804,190 distributed over , New York City is also the most densely populated major city in the U ...

, New York. There are hundreds of one-way pairs among the streets and avenues of New York City. One example is

Fifth Avenue Fifth Avenue is a major and prominent thoroughfare in the borough of Manhattan in New York City New York, often called New York City or NYC, is the most populous city in the United States. With a 2020 populatio ...

with Madison Avenue. Others include First Avenue with Second Avenue; Third Avenue with Lexington Avenue; and Seventh Avenue with either Sixth Avenue or Eighth Avenue. Two major streets in the city of

Pittsburgh Pittsburgh ( ) is a city in the Commonwealth (U.S. state), Commonwealth of Pennsylvania, United States, and the county seat of Allegheny County, Pennsylvania, Allegheny County. It is the most populous city in both Allegheny County and Wester ...

serve as a one-way pair; Forbes Avenue and

. Both streets begin in Downtown near Point State Park before becoming a one-way pair just east of Market Square, with Forbes serving outbound traffic and Fifth serving inbound traffic, going through

Uptown Uptown may refer to: Neighborhoods or regions in several cities United States * Uptown, entertainment district east of Downtown and Midtown Albuquerque, New Mexico * Uptown Charlotte, North Carolina * Uptown, area surrounding the University of C ...

and Oakland before both streets end up with two-way traffic and diverge, with Fifth Avenue eventually terminating in Highland Park, while Forbes terminates in 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 Portland (, ) is a port city in the Pacific Northwest and the largest city in the U.S. state of Oregon. Situated at the confluence of the Willamette and Columbia rivers, Portland is the county seat of Multnomah County, the most populou ...

, 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, 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 California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the ...

. These include 3rd and 4th Streets, 5th and 6th Streets, 8th and 9th Streets, 11th and 12th Streets, and Main and Spring Streets. Levick Street and Robbins Street in

Philadelphia Philadelphia, often called Philly, is the largest city in the Commonwealth of Pennsylvania, the sixth-largest city in the U.S., the second-largest city in both the Northeast megalopolis and Mid-Atlantic regions after New York City. Sinc ...

are considered a one-way pair. The streets carry traffic to and from the Tacony-Palmyra Bridge through the

Mayfair Mayfair is an affluent area in the West End of London towards the eastern edge of Hyde Park, in the City of Westminster, between Oxford Street, Regent Street, Piccadilly and Park Lane. It is one of the most expensive districts in the world ...

and Wissinoming neighborhoods. Between Frankford Avenue and Roosevelt Boulevard, the streets carry US 13 in their respective direction. In Orlando,

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, a ...

, 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.

References