Urban sprawl is a much-discussed aspect of urban patterns, and I will have frequent observations on this topic. Some of those comments will address the basic question of what we mean by sprawl, as a wide range of views have been offered. I will start off here by discussing several attempts to describe or define sprawl that do not reflect what I think is really meant by urban sprawl.
It is not uncommon to see sprawl described as endless urban development. While it’s easy to see where this comes from, it certainly cannot be taken as a useful definition of sprawl. This implies that the farther that urban development extends, the more an urban area sprawls. So the largest urban areas would be the most sprawling. This ignores the character of the development. The New York Urbanized Area, over 3,450 square miles, certainly extends over a much larger area than Phoenix, at 1,147 square miles, but we certainly would not want to conclude from this that urban sprawl in New York is greater.
A response might be that people don’t seriously consider the sheer extent of urban development to be indicative of sprawl, without considering the character of that development. But a look some of the images found in searches for “urban sprawl” in Google Images or Wikimedia Commons shows that some people mean exactly that. Along with the traditional views showing suburban sprawl are pictures that include dense urban cores, such as the photo of Tokyo shown here.
Closely related to sprawl as endless development would be to consider any new development at the urban fringe as being urban sprawl. I do not think any growth of an urban area should automatically be considered to be sprawl. It should depend on the character of the new development. To say that any new development at the fringe is sprawl is a rather pessimistic view that we are condemned to having more sprawl unless all urban expansion can be stopped.
Not that Wikipedia should be considered to be an authoritative source, but its article on urban sprawl gives as its first defination sprawl as unplanned growth (and they include citations to two scholarly articles supporting this). But this just doesn’t work. Most jurisdictions in large metropolitan areas in the United States have planning and zoning. Few are likely to agree that all of those areas are without urban sprawl. A response here is likely to be that most of those areas did not have “real” planning or that it was “bad” planning. This leads to the question of defining “bad” planning. It better not be planning that results in urban sprawl!
The opposite problem is just as significant. Central Boston is certainly an example of unplanned growth, but we would hardly cite that as an example of urban sprawl. Likewise for Manhattan, at least south of 14th Street and much of the island if one doesn’t count the 1803 laying out of the street grid as planning.
Finally, there are those who (seriously) have resorted to suggesting the use of the approach taken by Justice Potter Stewart in defining pornography: “I know it when I see it.” This was a completely unhelpful guide for pornography. Do you really think a religious fundamentalist and an ACLU member would draw the line in the same place? Similarly, this leaves urban sprawl as a totally individual, subjective concept that provides little basis for discussion and certainly none for measurement.