Cul de sac

A dead end, also known as a cul-de-sac, is a street with only one inlet/outlet. While historically built for other reasons, one of its modern uses is to calm vehicle traffic.

The term "dead end" is understood in all varieties of English, but the official terminology and traffic signs include many different alternatives. Some of these are used only regionally. In the United States and other countries, cul-de-sac (/ˈkʌldəsæk/ or /ˈkʊldəsæk/) is often not an exact synonym for dead end and refers to dead ends with a circular end, which makes it easy to turn around. See below for regionally used terms.

Dead ends existed in towns and cities long before the automotive 20th century, particularly in Arab and Moorish towns. The earliest example was unearthed in the El-Lahun workers' village in Egypt, which was built circa 1885 BC. The village is laid out with straight streets that intersect at right angles; akin to a grid, but irregular. The western part of the excavated village, where the workers lived, shows fifteen narrow and short dead-ends laid out perpendicularly on either side of a wider, straight street; all terminate at the enclosing walls.

Dead-end streets appeared also during the classical period of Athens and Rome. The 15th century architect and planner Leon Battista Alberti implies in his writings that dead-end streets may have been used intentionally in antiquity for defense purposes. He writes: “The Ancients in All Towns were for having some intricate Ways and turn again Streets [i.e.dead-ends or loops], without any Passage through them, that if an Enemy comes into them, he may be at a Loss, and be in Confusion and Suspense; or if he pushes on daringly, may be easily destroyed”. The same opinion is expressed by an earlier thinker, Aristotle, when he criticized the Hippodamian grid. He writes: “....but for security in war [the arrangement is more useful if it is planned in] the opposite [manner], as it used to be in ancient times. For that [arrangement] is difficult for foreign troops to enter and find their way about when attacking.”

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