There’s been a rather long ongoing debate on the Better Transport forums about whether sprawl or intensification is the best way to grow a city. In particular, issues relating to housing affordability, whether sprawl has to lead to auto-dependency, and the environmental effects of sprawl have become particularly debated. However, an interesting issue has come up which relates to the basic question of what is sprawl? People generally have the perception that it means a ‘spread out city’, one that is low density. I suppose that makes sense, as if I were to sprawl on a couch I would spread myself out upon it. However, in terms of ‘urban sprawl’ the matter is quite a bit more complex.
Here’s what i wrote about the matter in my 2005 thesis.
There are many characteristics that can be associated with the term ‘urban sprawl’, although there remains debate in the planning literature with regards to the development of an exact definition for the term, and disagreement whether particular urban forms should be categorised as urban sprawl or not. According to Gillham (2002) there are four main characteristics of sprawl, which mirror the earlier definition given by Nelson et. al. (1995). These characteristics are leapfrog or scattered development, commercial strip development, low density, and large expanses of single-use development.
Leapfrog and scattered development go beyond the urban fringe to create built-up communities that are isolated from the city by areas of undeveloped land. In many ways these can be seen as the most extreme examples of urban sprawl, with a highly inefficient use of the land, and a greater need to build highways and other infrastructure to service the outlying areas. Leapfrog development can be distinguished from ‘satellite towns’, a similar type of development beyond the urban fringe, by the former’s much lower density and once again the almost exclusive reliance on the automobile as the method of transport for those living in such areas. ‘The result is a haphazard patchwork, widely spread apart and seeming to consume far more land than contiguous developments’ (Gillham, 2002: 4), and even though the open tracts of land are usually filled in eventually, leapfrog development remains an inefficient use of land.
Commercial strip development, another aspect of urban sprawl, is characterised by ‘…huge arterial roads lined with shopping centres, gas stations, fast food restaurants, drive-thru banks, office complexes, parking lots and many large signs’ (Gillham, 2002: 5). ‘Strip development’ is very low density and automobile dependent, with retail configured in long, low boxes or in small pavilions which are always surrounded by large parking lots. Trips between the different retail outlets are almost always made by car, due to the ‘spread out’ nature of the strip, and there is little if any emphasis placed on the needs of pedestrians.
The third, and perhaps most commonly recognised aspect of urban sprawl, is its low density. Gillham (2002) describes the density of urban sprawl as lying between that that of the crowded urban core and open countryside, but being much lower than older towns and cities. Buildings in ‘sprawl’ developments are generally single-story, widely spaced and with intervening parking lots and roadways. Density is normally measured in terms of population density, or dwelling units per area. A population density of fewer than 25 people per hectare is generally considered ‘low density’, and would include most North American, Australian and New Zealand cities, but exclude many in Europe which have a density of around 50 people per hectare, or Asian cities which often have densities of over 100 people per hectare (Elkin et. al., 1991). However, often a more useful measure than population or dwelling density in measuring urban sprawl can be ‘floor area ratio (FAR)’. FAR is the ratio of the area built up to the total land area, meaning that built commercial space can also be measured by dividing the shop floor size by the total land area of the retail outlet. Rural farmland generally has an FAR of between 0.0005 and 0.02, indicating a very low density, with its built-up area accounting for only between 0.05 and two per cent of total land area. Suburban areas, with which sprawl is associated, generally have an FAR of between 0.05 and 0.18 which reflects their low density as less than 20 per cent of the total land area being occupied by buildings. This contrasts with inner urban densities which can range from 0.88 for townhouses right up to 5.05 for apartment buildings (Gillham, 2002: 6).
However, there is clearly more to sprawl than just low density. The final aspect of urban sprawl, the proliferation of single-use development and an almost exclusive reliance on automobiles for transportation, is just as important as density in the identification of urban sprawl, especially the negative environmental, economic and social effects that it contributes to. As mentioned above, single-use development originated as a positive response to the problems of early industrialised cities, and is often created very deliberately through zoning legislation and other subdivision bylaws. However, after World War II the separation of land uses has been taken to the extreme, with large spatial separation between all the different facilities meaning that the only plausible method of transportation is the automobile.
According to Nozzi (2003), city design today means that travelling via an automobile is a necessity, as there is no other way to transport children, groceries, and conduct other multidestination activities, with the convenience of the ‘always available’ car. The mixed-use, higher-density developments of early twentieth century cities, which facilitated both walking and the use of public transport, have been usurped by spatially dispersed cities and ‘bedroom communities’ of exclusive residential development, realistically accessible only by car.
In posts coming up I will start to talk more about good aspects of sprawl and bad aspects of sprawl, and also how this all connects to transport. Though for now I think it’s safe to say that I consider auto-dependency to be the most telling sign of urban sprawl – rather than low density development.
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