Traffic circle


Traffic circle

A traffic circle is an intersection with a circular shape and, usually, a central island. In some traffic circles two-way traffic is allowed within the circle. It is much more common, however, that traffic is allowed to go in one direction only around a central island. Traditionally, traffic entering a circle has the right-of-way, although some circles give right-of-way to the primary roads. In roundabouts, as opposed to traffic circles,Fact|Please give a source for this distinction. Are these definitions identical in every country?| ()|date=September 2008 entering traffic must yield to traffic already in the circulatory roadway.

History

French architect Eugène Hénard was designing one-way circular intersections as early as 1877 [P. M. Wolf, "Eugene Henard and the Beginning of Urbanism in Paris, 1900–1914", International Federation for Housing and Planning, The Hague, 1969, cited by Ben Hamilton-Baillie & Phil Jones, "Improving traffic behaviour and safety through urban design", Proceedings of ICE - Civil Engineering, volume 158 Issue 5 May 2005 p. 41 http://www.hamilton-baillie.co.uk/papers/ICE_paper_April05.pdf ] . American architect William Phelps Eno favored small traffic circles. He designed New York City's famous Columbus Circle, which was built in 1905. Other traffic circles were subsequently built in the United States. Many were large diameter 'rotaries' that enabled high speed merge and weave, and gave priority to the traffic entering the circle. These designs were doomed to failure for two primary reasons:
*It takes a large diameter circle to provide enough room for merging at speed. Although some of these circles were huge (many were in excess of 100 meters or 300 feet in diameter), they weren't large enough for high-speed merging.
*Giving priority to entering traffic means that more vehicles can enter the circulatory roadway than it can handle. The result is congestion within the circle.

The experience with traffic circles in the US was almost entirely negative, characterized by high accident rates and congestion problems. By the mid 1950s, construction of traffic circles had ceased entirely. The experience with traffic circles in other countries was not much better until the development of the modern roundabout in the United Kingdom during the 1960s.

Among the most famous traffic circles in the world is that of Canberra, Australia, where a large traffic circle encircles Parliament House. This circle has traffic lights at each major intersection within the circle.

The largest traffic circle in the world is claimed to be one of those in the Dammam coastal road, Al-Khaleej Street, in Saudi Arabia with a length of approximately 1.9 km (1.20 miles) [http://wikimapia.org/#lat=26.463451&lon=50.07276&z=18&l=0&m=a&v=2&show=/1091544/] wikimapia.org] .

Composition

Traffic circles are often composed of concrete or asphalt although more recently rubber curbing is being used to create traffic circles as well, primarily in residential areas. Rubber curbing consists of units of flexible rubber that are bent and installed around a landscaped area to create traffic circles.

ource

ee also

*List of traffic circles in New Jersey
*List of Circles in Washington, D.C.
*Roundabout


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • traffic circle — traffic .circle n AmE a circular place where two or more roads join, which all traffic must drive around British Equivalent: roundabout …   Dictionary of contemporary English

  • traffic circle — traffic ,circle noun count AMERICAN a part of a road in the shape of a circle that other roads join. British roundabout …   Usage of the words and phrases in modern English

  • traffic circle — traffic circles N COUNT A traffic circle is a circular structure in the road at a place where several roads meet. You drive round it until you come to the road that you want. [AM] (in BRIT, use roundabout) …   English dictionary

  • traffic circle — ☆ traffic circle n. a circular street at the intersection of several streets with vehicles traveling in one direction only, designed to facilitate the flow of traffic; rotary …   English World dictionary

  • traffic circle — UK / US noun [countable] Word forms traffic circle : singular traffic circle plural traffic circles American a roundabout I, 1) …   English dictionary

  • traffic circle — noun a road junction at which traffic streams circularly around a central island the accident blocked all traffic at the rotary • Syn: ↑circle, ↑rotary, ↑roundabout • Hypernyms: ↑junction • Part Holonyms: ↑ …   Useful english dictionary

  • traffic circle — An intersection of several roads where the traffic goes around a central circle and goes out another road. Although it is a rapid way of negotiating an intersection, many people are intimidated by it because of its unfamiliarity. The British term …   Dictionary of automotive terms

  • traffic circle — An intersection, sometimes involving several streets, intended to facilitate traffic in moving from one street to another by being arranged and posted for movement of vehicles one way and in a circle. 7 Am J2d Auto § 203 …   Ballentine's law dictionary

  • traffic circle — noun Date: 1942 rotary 2 …   New Collegiate Dictionary

  • traffic circle — a circular arrangement constructed at the intersection of two or more roads in order to facilitate the passage of vehicles from one road to another. Also called rotary; Brit., roundabout. [1945 50] * * * …   Universalium


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