Urban density is a term used in
urban planning and
urban design to refer to the number of people inhabiting a given
urbanized area. As such it is to be distinguished from other measures of
population density. 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.
Urban density and sustainability
It is commonly asserted that higher density cities are more sustainable than low density cities. Much
planning theory, particularly in North America, the UK, Australia and New Zealand has been developed premised on raising urban densities, such as
New Urbanism,
Transit-oriented development, and
Smart growth.
However, the link between urban density and aspects of
sustainability remains a contested area of
planning theory. Many experts on
sustainable urbanism argue that low-density, dispersed cities are unsustainable as they are
automobile dependent. Others counter that raising densities results in more expensive real estate, greater road congestion and more air pollution. At a broader level though, 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.
Measuring urban density
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:
- Floor area ratio - the total floor area of buildings divided by land area of the lot they are built on
- 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.
- Weighted density - a density metric which measures the density at which the average citizen 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.
See also
Footnotes
