Urban density
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Urban density is a concept used in
urban planning Urban planning (also called city planning in some contexts) is the process of developing and designing land use and the built environment, including air, water, and the infrastructure passing into and out of urban areas, such as transportatio ...
,
urban studies Urban studies is based on the study of the urban development of cities and regions—it makes up the theory portion of the field of urban planning. This includes studying the history of city development from an architectural point of view, to th ...
, and related fields to describe the intensity of people, jobs, housing units, total floor area of buildings, or some other measure of human occupation, activity, and development across a defined unit of area. In general terms, urban density describes the degree of concentration or
compactness In mathematics, specifically general topology, compactness is a property that seeks to generalize the notion of a closed and bounded subset of Euclidean space. The idea is that a compact space has no "punctures" or "missing endpoints", i.e., it ...
of people or development in a city. As such it is to be distinguished from other measures of
population density Population density (in agriculture: Standing stock (disambiguation), standing stock or plant density) is a measurement of population per unit land area. It is mostly applied to humans, but sometimes to other living organisms too. It is a key geog ...
. Urban density is considered an important factor in understanding how cities function. Research related to urban density occurs across diverse areas, including economics, health, innovation, psychology and geography as well as
sustainability Sustainability is a social goal for people to co-exist on Earth over a long period of time. Definitions of this term are disputed and have varied with literature, context, and time. Sustainability usually has three dimensions (or pillars): env ...
. A 2019 meta-analysis of 180 studies on a vast number of economic outcomes of urban density concluded that urban density had net positive effects. However, there may be some regressive distributional effects.


Sustainability

It is commonly asserted that higher-density cities are more sustainable than low-density cities. This is because they reduce urban sprawl, minimize land use, and make services and infrastructure more efficient and accessible to residents. Much urban planning theory - particularly in North America, the UK, Australia, and New Zealand - has been developed premised on raising urban densities, such as
New Urbanism New Urbanism is an urban design movement that promotes environmentally friendly habits by creating Walkability, walkable neighbourhoods containing a wide range of housing and job types. It arose in the United States in the early 1980s, and has ...
,
transit-oriented development In urban planning, transit-oriented development (TOD) is a type of Real estate development, urban development that maximizes the amount of Residential area, residential, business and leisure space within Pedestrian, walking distance of public t ...
, and
smart growth Smart growth is an urban planning and transportation theory that concentrates growth in compact walkable urban centers to avoid sprawl. It also advocates compact, transit-oriented, walkable, bicycle-friendly land use, including neighborhood ...
. This assertion, however, remains a contested or challenged one. The link between urban density and aspects of
sustainability Sustainability is a social goal for people to co-exist on Earth over a long period of time. Definitions of this term are disputed and have varied with literature, context, and time. Sustainability usually has three dimensions (or pillars): env ...
remains a contested area of planning theory.
Jan Gehl Jan Gehl Hon. FAIA (born 17 September 1936, Copenhagen) is a Danish architect and urban design consultant based in Copenhagen whose career has focused on improving the quality of urban life by re-orienting city design towards the pedestrian an ...
, prominent Urban Designer and expert on sustainable urbanism, argues that low-density, dispersed cities are unsustainable as they are automobile dependent. NASA, for example, has established a direct correlation between urban density and
air pollution Air pollution is the presence of substances in the Atmosphere of Earth, air that are harmful to humans, other living beings or the environment. Pollutants can be Gas, gases like Ground-level ozone, ozone or nitrogen oxides or small particles li ...
. Others, such as Randal O'Toole of the
libertarian Libertarianism (from ; or from ) is a political philosophy that holds freedom, personal sovereignty, and liberty as primary values. Many libertarians believe that the concept of freedom is in accord with the Non-Aggression Principle, according ...
Cato Institute The Cato Institute is an American libertarian think tank headquartered in Washington, D.C. It was founded in 1977 by Ed Crane, Murray Rothbard, and Charles Koch, chairman of the board and chief executive officer of Koch Industries.Koch ...
, point to how raising densities results in more expensive real estate, greater road congestion, and more localized air pollution. At a broader level, there is evidence to indicate a strong negative correlation between the total energy consumption of a city and its overall urban density, i.e. the lower the density, the more energy consumed. The location and urban setting where densification processes occur therefore need to be considered for sustainable densification.


Measurement

Urban density is a very specific measurement of the population of an urbanized area, excluding non-urban land-uses. Non-urban uses include regional open space, agriculture and water-bodies. There are a variety of other ways of measuring the density of urban areas: *
Population density Population density (in agriculture: Standing stock (disambiguation), standing stock or plant density) is a measurement of population per unit land area. It is mostly applied to humans, but sometimes to other living organisms too. It is a key geog ...
- the number of human persons per unit area ** Median density - a density metric which measures the density at which the average person lives. It is determined by ranking the census tracts by population density, and taking the density at which fifty percent of the population lives at a higher density and fifty percent lives at a lower density. ** Population-weighted density - a density metric which measures the density at which the average person lives. It is determined by calculating the standard density of each census tract, assigning each a weight equal to its share of the total population, and then adding the segments. * Residential density - the number of dwelling units in any given area * Floor area ratio - the total floor area of buildings divided by land area of the lot upon which the buildings are built * Employment density - the number of jobs in any given area * Gross density - any density figure for a given area of land that includes uses not necessarily directly relevant to the figure (usually roads and other transport infrastructure) * Net density - a density figure for a given area of land that excludes land not directly related to the figure.


Impact

A 2019 meta-analysis of 180 studies on a vast number of economic outcomes of urban density concluded that urban density had net positive effects. However, there may be some regressive distributional effects. A 2020 study concluded that urban density "boosts productivity and innovation, improves access to goods and services, reduces typical travel distances, encourages energy efficient construction and transport, and allows broader sharing of scarce urban amenities. However, density is also synonymous with crowding and makes living and moving in cities more costly."


See also

* Compact city *
List of cities proper by population density This is a list of cities worldwide by population density. The population, population density and land area for the cities listed are based on the entire city proper, the defined boundary or border of a city or the city limits of the city. The ...
*
List of countries and dependencies by population density This is a list of countries and dependencies ranked by population density, sorted by habitants per square kilometre or square mile. The list includes sovereign states and self-governing dependent territories based upon the ISO standard ISO 31 ...
*
Smart growth Smart growth is an urban planning and transportation theory that concentrates growth in compact walkable urban centers to avoid sprawl. It also advocates compact, transit-oriented, walkable, bicycle-friendly land use, including neighborhood ...
*
Transportation planning Transportation planning is the process of defining future policies, goals, investments, and spatial planning designs to prepare for future needs to move people and goods to destinations. As practiced today, it is a collaborative process that i ...
*
Urban sprawl Urban sprawl (also known as suburban sprawl or urban encroachment) is defined as "the spreading of urban developments (such as houses and shopping centers) on undeveloped land near a city". Urban sprawl has been described as the unrestricted ...
*
Urban vitality Urban vitality is the quality of spaces in urban area, cities that attract diverse groups of people for a range of activities at different times of the day. Such spaces are often be perceived as being alive, lively or vibrant, in contrast with lo ...
* Verticalization * Population-weighted density


References


Further reading

* Newman, P and Kenworthy, J (1999) Cities and Sustainability: Overcoming automobile dependence, Washington, D. C. : Island Press * Pont, Meta Y. Berghauser and Haupt, Per (2010) ''Spacematrix: Space, Density and Urban Form'', NAi Publishers, * Dovey, Kim and Pafka, Elek (2014) "The urban density assemblage: Modelling multiple measures" in ''Urban Design International'', vol.19, nr. 1, pg.66-76


External links


MIT Density Atlas


{{DEFAULTSORT:Urban density Sustainable urban planning