Urban planning

'''Urban, city,''' or town planning, deals with design of the built environment from the municipal and metropolitan perspective. Other professions deal in more detail with a smaller scale of development, namely architecture and urban design. Regional planning deals with a still larger environment, at a less detailed level. The Greek Hippodamus is often considered the father of city planning, for his design of Miletus, though examples of planned cities permeate antiquity. Muslims are thought to have originated the idea of formal zoning (see haram and hima and the more general notion of khalifa, or "stewardship" from which they arise), although modern usage in the West largely dates from the ideas of the Congres Internationaux d'Architecture Moderne. City planning embraces the organization, or conscious influencing, of land-use distribution in an area already built-up or intended to become built-up.

History

The Indus Valley civilization is recognized as having been the first to develop urban planning. By 2600 BC some pre-Harappan settlements grew into cities containing thousands of people who were not primarily engaged in agriculture, creating a unified culture whose sudden appearance appears to have been the result of planned, deliberate effort. Some settlements appear to have been deliberately rearranged to conform to a conscious, well-developed plan. For this reason, the Indus Valley civilization is recognized as having first developed urban planning. In ancient times, Romans used a consolidated scheme for city planning, developed for military defense and civil convenience. Effectively, many European towns still preserve the essence of these schemes, as in Turin. The basic plan is a central plaza with city services, surrounded by a compact grid of streets and wrapped in a wall for defense. To reduce travel times, two diagonal streets cross the square grid corner-to-corner, passing through the central square. A river usually flows through the city, to provide water and transport, and carry away sewage, even in sieges.

Planning and aesthetics

In developed countries there has been a backlash against excessive man-made clutter in the environment, such as bollards (signposts), signs, and hoardings (temporary fences around construction sites). Other issues that generate strong debate amongst urban designers are tensions between peripheral growth, increased housing density and planned new settlements. There are also unending debates about the benefits of mixing tenures and land uses, versus the benefits of distinguishing geographic zones where different uses predominate. Successful urban planning considers character, of "home" and "sense of place", local identity, respect for natural, artistic and historic heritage, an understanding of the "urban grain" or "townscape," pedestrians and other modes of traffic, utilities and natural hazards, such as flood zones. Some say that the medieval piazza and arcade are the most widely appreciated elements of successful urban design, as demonstrated by the Italian cities of Siena and Bologna. While it is rare that cities are planned from scratch (and, in case, with some risk of unsuccessful examples like for Brasília), planners are important in managing the growth of cities, applying tools like zoning to manage the uses of land, and growth management to manage the pace of development. When examined historically, many of the cities now thought to be most beautiful are the result of dense, long lasting systems of prohibitions and guidance about building sizes, uses and features. These allowed substantial freedoms, yet enforce styles, safety, and often materials in practical ways. Many conventional planning techniques are being repackaged as smart growth. There are some cities that have been planned from conception, and while the results often don't turn out quite as planned, evidence of the initial plan often remains. See List of planned cities. Some of the most successful planned cities consist of cells that include park-space, commerce and housing, and then repeat the cell. Usually cells are separated by streets. Often each cell has unique monuments and gardening in the park, and unique gates or boundary-markers for the edges of the cell. The commercial areas naturally become diverse. These differences help instill a sense of place, while the similarities of the cells make each place in the city familiar.

Planning and safety

Many cities are constructed in places subject to flood, storm surges, extreme weather or war. City planners can cope with these. If the dangers can be localized (for flood or storm surge), the affected regions can be made into parkland or greenbelt, often with lovely results. Another practical method is simply to build the city on ridges, and the parks and farms in valleys. Extreme weather, flood, war or other emergencies can often be greatly mitigated with secure evacuation routes and emergency operations centers. These are relatively inexpensive and unintrusive, and many consider them a reasonable precaution for any urban space. Many cities also have planned, built safety features, such as levees, retaining walls, and shelters. Some planning methods might help an elite group to control ordinary citizens. This was certainly the case of Rome (Italy), where Fascism in the 1930s created ex novo many new suburbs in order to concentrate criminals and poorer classes away from the elegant town. France currently uses similar methods to control ethnic-Arabic groups on welfare. In recent years, practitioners have also been expected to maximize the accessibility of an area to people with different abilities, practising the notion of "inclusive design," to anticipate criminal behavior and consequently to "design-out crime" and to consider "traffic calming" or "pedestrianization" as ways of making urban life more bearable. City planning tries to control criminality with structures designed from theories like socio-architecture or environmental determinism. These theories say that an urban environment can influence individuals' obedience to social rules. The theories often say that psychological pressure develops in more densely developed, unadorned areas. This stress causes some crimes and some use of illegal drugs. The antidote is usually more individual space and better, more beautiful design in place of functionalism. Other social theories point out that in England and most countries since the 18th century, the transformation of societies from rural agriculture to industry caused a difficult adaptation to urban living. These theories emphasize that many planning policies ignore personal tensions, forcing individuals to live in a condition of perpetual extraneity to their cities. Many people therefore lack the comfort of feeling "at home" when at home. Often these theorists seek a reconsideration of commonly used "standards" that rationalize the outcomes of a free (relatively unregulated) market.

Planning and transport

There is a direct, well-researched connection between the density of an urban environment, and the amount of transport into that environment. Good quality transport is often followed by development. Development beyond a certain density can quickly overcrowd transport. Good planning attempts to place higher densities of jobs or residents near high-volume transport. For example, some cities permit commerce and multi-storey apartment buildings only within one block of train stations and four-lane boulevards, and accept single-family dwellings and parks further away. Densities are usually measured as the floor area of buildings divided by the land area, or in a residential context, by the number of dwellings divided by the land area. Floor area ratios below 1.5 are low density. Plot ratios above five are very high density. Most exurbs are below two, while most city centers are well above five. Walk-up apartments with basement garages can easily achieve a density of three. Skyscrapers easily achieve densities of thirty or more. Higher densities tempt developers with higher profits. City authorities may try to encourage lower densities to reduce infrastructure costs, though some observers note that low densities may not accommodate enough population to provide adequate demand or funding for that infrastructure. Automobiles are well suited to serve densities as high as 1.5 with basic limited-access highways. Innovations such as car-pool lanes and rush hour-use taxes may get automobiles to neighbourhoods with plot ratios as high as 2.5. Densities above 5 are well-served by trains. Most such areas were actually developed in response to trains in the middle 1800s, and have historically high ridership that have never used automobiles for their work trip. A widespread problem is that there is a range of residential densities between about two and five that causes severe traffic jams of automobiles, yet are too low to be commercially served by trains or light rail. The conventional solution is to use buses, but these and light rail systems may fail where automobiles and excess road network capacity are both available, achieving less than 1% ridership. Some theoretricians speculate that personal rapid transit might coax people from their automobiles, and yet effectively serve intermediate densities, but this has not been demonstrated. The Lewis-Mogridge Position claims that increasing road space is not an effective way of relieving traffic jams as latent or induced demand invariably emerges to restore a socially-tolerable level of congestion.

Planning and suburbanization

In some countries declining satisfaction with the urban environment is held to blame for continuing migration to smaller towns and rural areas (so-called urban exodus), so successful urban planning can bring benefits to a much larger hinterland or city region and help to reduce both congestion along transport routes and the wastage of energy implied by excessive commuting. A strong belief that the behaviour of individuals living in or frequenting an area can be heavily influenced by its physical design and layout is called environmental determinism.

Planning and the environment

Arcology seeks to unify the fields of ecology and architecture, especially landscape architecture, to achieve a harmonious environment for all living things. On a small scale, the eco-village theory has become popular, as it emphasizes a traditional 100-140 person scale for communities. In most advanced urban or village planning models, local context is critical. In many, gardening assumes a central role not only in agriculture but in the daily life of citizens. A series of related movements including green anarchism, eco-anarchism, eco-feminism and Slow Food have put this in a political context as part of a focus on smaller systems of resource extraction, and waste disposal, ideally as part of living machines which do such recycling automatically, just as nature does. The modern theory of natural capital emphasizes this as the primary difference between natural and infrastructural capital, and seeks an economic basis for rationalizing a move back towards smaller village units. A common form of planning that leads to suburban sprawl is single use zoning.

References

See also

cy:Cynllunio tref da:Byplanlćgning de:Stadtplanung fr:Urbanisme es:Urbanismo id:Perencanaan kota ja:都市計画 lb:Urbanismus nl:Planologie pt:Planejamento urbano vi:Quy hoạch đô thị zh:城市规划

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