Zoning
In urban planning, zoning is a method in which a municipality or other tier of government divides land into land-use and building "zones", each of which has a set of regulations for new development that differs from other zones. Zones may be defined for a single use, they may combine several compatible activities by use, or in the case of form-based zoning, the differing regulations may govern the density, size and shape of allowed buildings whatever their use. The planning rules for each zone determine whether planning permission for a given development may be granted. Zoning may specify a variety of outright and conditional uses of land. It may indicate the size and dimensions of lots that land may be subdivided into, or the form and scale of buildings. These guidelines are set in order to guide urban growth and development.
Zoning is the most common regulatory urban planning method used by local governments in developed countries. Exceptions include the United Kingdom and the city of Houston, Texas.
Most zoning systems have a procedure for granting variances, usually because of some perceived hardship caused by the particular nature of the property in question.
History
The origins of zoning districts can be traced back to antiquity. The ancient walled city was the predecessor for classifying and regulating land, based on use. Outside the city walls were the undesirable functions, which were usually based on noise and smell. The space between the walls is where unsanitary and dangerous activities occurred such as butchering, waste disposal, and brick-firing. Within the walls were civic and religious places, and where the majority of people lived.Beyond distinguishing between urban and non-urban land, most ancient cities further classified land types and uses inside their walls. This was practiced in many regions of the world – for example, in China during the Zhou Dynasty, in India during the Vedic Era, and in the military camps that spread throughout the Roman Empire.
Throughout the Age of Enlightenment and Industrial Revolution, cultural and socio-economic shifts led to the rapid increase in the enforcement and invention of urban regulations. The shifts were informed by a new scientific rationality, the advent of mass production and complex manufacturing, and the subsequent onset of urbanisation. Industry leaving the home reshaped modern cities. The definition of home was tied to the definition of economy, which caused a much greater mixing of uses within the residential quarters of cities.
Separation between uses is a feature of many planned cities designed before the advent of zoning. A notable example is Adelaide in South Australia, whose city centre, along with the suburb of North Adelaide, is surrounded on all sides by a park, the Adelaide Park Lands. The park was designed by Colonel William Light in 1836 in order to physically separate the city centre from its suburbs. Low density residential areas surround the park, providing a pleasant walk between work in the city within and the family homes outside.
Sir Ebenezer Howard, founder of the garden city movement, cited Adelaide as an example of how green open space could be used to prevent cities from expanding beyond their boundaries and coalescing. His design for an ideal city, published in his 1902 book Garden Cities of To-morrow, envisaged separate concentric rings of public buildings, parks, retail space, residential areas and industrial areas, all surrounded by open space and farmland. All retail activity was to be conducted within a single glass-roofed building, an early concept for the modern shopping centre inspired by the Crystal Palace.
However, these planned or ideal cities were static designs embodied in a single masterplan. What was lacking was a regulatory mechanism to allow the city to develop over time, setting guidelines to developers and private citizens over what could be built where. The first modern zoning systems were applied in the United States with the Los Angeles zoning ordinances of 1904 and the New York City 1916 Zoning Resolution.
But the first formal zoning ordinance in the United States was aimed at racial segregation. In 1885, the city of Modesto, California passed a law restricting the establishment of laundries into the city's Chinatown, a move aimed at stopping the encroachment of Chinese immigrants into previously white areas of the city.
Types
There are a great variety of zoning types, some of which focus on regulating building form and the relation of buildings to the street with mixed uses, known as form-based, others with separating land uses, known as use-based, or a combination thereof. Use-based zoning systems can comprise single-use zones, mixed-use zones - where a compatible group of uses are allowed to co-exist - or a combination of both single and mixed-use zones in one system.The main approaches include use-based, form-based, performance and incentive zoning. There are also several additional zoning provisions used in combination with the main approaches.
Main approaches to zoning
Use-based zoning
Use-based or functional zoning systems can comprise single-use zones, mixed-use zones—where a compatible group of uses are allowed to co-exist —or a combination of both single- and mixed-use zones in one system.Single-use zoning
The primary purpose of single-use zoning is to geographically separate uses that are thought to be incompatible. In practice, zoning is also used to prevent new development from interfering with existing uses and/or to preserve the character of a community.Single-use zoning is where only one kind of use is allowed per zone, or district. It is also known as exclusionary zoning or, in the United States, as Euclidean zoning because of a court case in Euclid, Ohio, Village of Euclid, Ohio v. Ambler Realty Co., which established its constitutionality. It has been the dominant system of zoning in North America, especially the United States, since its first implementation.
Commonly defined single-use districts include: residential, commercial, and industrial. Each category can have a number of sub-categories, for example, within the commercial category there may be separate districts for small retail, large retail, office use, lodging and others, while industrial may be subdivided into heavy manufacturing, light assembly and warehouse uses. Special districts may also be created for purposes like public facilities, recreational amenities, and green space.
The application of single-use zoning has led to the distinctive form of many cities in the United States, Canada, Australia, and New Zealand, in which a very dense urban core, often containing skyscrapers, is surrounded by low density residential suburbs, characterised by large gardens and leafy streets. Some metropolitan areas such as Minneapolis–Saint Paul and Sydney have several such cores.
Mixed-use zoning
Mixed-use zoning combines residential, commercial, office, and public uses into a single space. Mixed-use zoning can be vertical, within a single building, or horizontal, involving multiple buildings.Planning and community activist Jane Jacobs wrote extensively on the connections between the separation of uses and the failure of urban renewal projects in New York City. She advocated dense mixed-use developments and walkable streets. In contrast to villages and towns, in which many residents know one another, and low-density outer suburbs that attract few visitors, cities and inner city areas have the problem of maintaining order between strangers. This order is maintained when, throughout the day and evening, there are sufficient people present with eyes on the street. This can be accomplished in successful urban districts that have a great diversity of uses, creating interest and attracting visitors. Jacobs' writings, along with increasing concerns about urban sprawl, are often credited with inspiring the New Urbanism movement.
To accommodate the New Urbanist vision of walkable communities combining cafés, restaurants, offices and residential development in a single area, mixed-use zones have been created within some zoning systems. These still use the basic regulatory mechanisms of zoning, excluding incompatible uses such as heavy industry or sewage farms, while allowing compatible uses such as residential, commercial and retail activities so that people can live, work and socialise within a compact geographic area.
The mixing of land uses is common throughout the world. Mixed-use zoning has particular relevance in the United States, where it is proposed as a remedy to the problems caused by widespread single-use zoning.
Form-based zoning
Form-based or intensity zoning regulates not the type of land use, but the form that land use may take. For instance, form-based zoning in a dense area may insist on low setbacks, high density, and pedestrian accessibility. Form-based codes are designed to directly respond to the physical structure of a community in order to create more walkable and adaptable environments.File:Eiffel_Tower_from_the_Tour_Montparnasse_3,_Paris_May_2014.jpg|thumb|Paris, looking toward the high density district of La DéfenseForm-based zoning codes have five main elements: a regulating plan, public standards, building standards, and precise definitions of technical terms. Form-based codes recognize the interrelated nature of all components of land-use planning—zoning, subdivision, and public works—and integrate them to define districts based on the community's desired character and intensity of development.
The French planning system is mostly form-based; zones in French cities generally allow many types of uses. The city of Paris has used its zoning system to concentrate high-density office buildings in the district of La Défense rather than allow heritage buildings across the city to be demolished to make way for them, as is often the case in London or New York. The construction of the Montparnasse Tower in 1973 led to an outcry. As a result, two years after its completion the construction of buildings over seven storeys high in the city centre was banned.