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A cul-de-sac , dead end (British, Canadian, American, South African English, and Australian English), closed, no through road, a close (British, Canadian, and Australian English), no exit (New Zealand English) or court (American, Australian English) is a street with only one inlet/outlet. While historically built for other reasons, one of its modern uses is to calm vehicle traffic. ==History== Culs-de-sac have appeared in plans of towns and cities before the automotive 20th century, particularly in Arab and Moorish towns. The earliest example of cul-de-sac streets was unearthed in the El-Lahun workers village in Egypt, which was built circa 1885 BCE. 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-end streets 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 〔Leon Battista Alberti, Ten Books on Architecture, 1485, ed. James Rykwert(New York: Transatlantic Arts, 1966) Book IV, Ch. V. 75〕 that dead-end streets may have been used intentionally in antiquity for defence purposes. He writes: “The Ancients in All Towns were for having some intricate Ways and turn again Streets (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 (arrangement is more useful if it is planned in ) the opposite (), as it used to be in ancient times. For that () is difficult for foreign troops to enter and find their way about when attacking.”〔Aristotle, The Politics, 335-323, trans. T.A. Sinclair(New York: Penguin, 1962) Book VII, section xi. 422〕 In the UK, their prior existence is implied by an 1875 law which banned their use in new developments. Inferential evidence of their earlier use can also be drawn from the text of a German architect, Rudolf Eberstadt, that explains their purpose and utility: “We have, in our medieval towns, showing very commendable methods of cutting up the land. I ought to mention here that to keep traffic out of residential streets is necessary not only in the general interest of the population, but, above all, for the sake of the children, whose health (amongst the working classes) is mainly dependent on the opportunity of moving about in close connection with their dwelling places, without the danger of being run over. In the earlier periods, traffic was excluded from residential streets simply by gates or by employing the cul-de-sac”. It was in the UK that the cul-de-sac street type was first legislated into use, with The Hampstead Garden Suburb Act 1906. The proponents of the Act, Raymond Unwin and Barry Parker, thus gained permission to introduce culs-de-sac in their subsequent site plans, and they promoted it as a suitable street type for Garden Suburbs. Unwin's applications of the cul-de-sac and the related crescent always included pedestrian paths independent of the road network. This design feature reflects the predominance of pedestrian movement for local trips at the turn of the 20th century, and presages the current planning priority for increased pedestrian accessibility. The 1906 Act defined the nature of the cul-de-sac as a non-through road and restricted its length to . Garden cities in the UK that followed Hampstead, such as Welwyn Garden City all included culs-de-sac (see photo). In the 1920s, the garden city movement gained ground in the US and, with it, came its design elements, such as the cul-de-sac. Clarence Stein, a main proponent of the movement, incorporated it in the Radburn, NJ subdivision, which was to become a model for subsequent neighbourhood developments. The US Federal Housing Authority recommended and promoted their use through their 1936 guidelines and the power of lending development funds. In Canada, a variation of Stein’s Radburn 1929 plan that used crescents (loops) instead of culs-de-sac was built in 1947 in Manitoba, Wildwood Park, Winnipeg, designed by Hubert Bird. In 1954, the Central Mortgage and Housing Corporation published its own guidelines in which the cul-de-sac was strongly recommended for local streets and, as the FHA in the US, used its lending power to see its inclusion in development plans. The Varsity Village and Braeside, subdivisions in Calgary, Alberta also used the Radburn model in the late 1960s. In the 1960s the cul-de-sac attained systematic international application in planned new cities such as Doxiadis’ Islamabad (1960). In the UK new towns such as Harlow (1947) by Sir Frederick Gibberd and Milton Keynes (1967) incorporated culs-de-sac and crescents in their layouts Planning theorists have suggested the use alternatives to culs-de-sac most notably, Christopher Alexander et al., in his “A Pattern Language” 1977 book (pattern #49) suggests the use of looped local roads which do no abruptly stop. Although dead end streets, i.e. culs-de-sac, would fit his definition of looped local roads Alexander suggestions that "culd-de-sacs are very bad from a social standpoint–they force interaction and they feel claustrophobic, because there is only one entrance". Doxiadis has additionally argued their important role in separating man from machine. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Cul-de-sac」の詳細全文を読む スポンサード リンク
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