A simple graduated symbol map from Governing.com shows the range of commuter rates for cities – with a roll-over for specific cities to show more detail. The map for Bike Commuters shows a comparison of commuters to total workers – so each is proportional. The high margin of error in the data (which in the notes is attributed to 2006 and 2011 American Community Survey – ACS) means, as with all maps and data, one must take it with a grain of salt.
To compare, another map on the site shows total people who Bike to Work – which could be construed as the same thing, and obviously there would be some correlation – but is a specific question and not a comparison of bike commuters to overall workers, as shown above, so does make for a slightly different spread – for instance Eugene, Oregon – which is larger on the above map – is significantly smaller on the map below – because the plot is based on total riders – so obviously Portland would be bigger due to larger population.
There a lot of information out there related to aspects of urbanism in its many facets, so in the spirit of academia, a feature here at THINK.urban will be to regularly compile and summarize some recent articles, posts, and other resources. These are brief elements that don’t get their own post, but are interesting reading and worth sharing. And, if you find something of interest, feel free to send us an email and we will include it in upcoming posts.
The Ecology of Disease (NY Times | 07/14/12) The spread of infections diseases and pandemics can be linked to development, as the delicate balance of biodiversity keeps potential disaster at bay, and increasing encroachment and urbanization could erode that balance.
The New Geography of the Working Class (Atlantic Cities | 07.12/12) Love him or hate him, Richard Florida keeps on trucking along, with analysis of the production side of the geographic economy in the US.
Terwilliger Parkway celebrates 100 years (DJC Oregon | 07/19/12) Celebrating the parkway legacy and citywide park system envisions over a century ago by John C. Olmsted, and the dearth of landscapes for mobility that are possible in todays society.
The constantly shifting definition of ‘City’ or ‘Urban’ makes for some ambiguity in talking about our aggregations (or is that agglomerations?) of development. Grist mentions the perceived dilemma with contradictions that the 2010 census shows that cities are adding population faster than suburbs for the first time in the last century, while also finding documentation from Atlantic Cities that exurbs are the fastest growing areas in the US. Are we talking about the same things? Is it just semantics, or does this difference between suburb, exurb, fringe, metro area actually make sense? Is a suburb and an exurb the same thing? Or is one a low-density, non-urban entity (suburb) with it’s parallel, urban counterpart of low-density development (exurb). Is it purely based on density and type of development, or is proximity to center make a difference? Does a center exist, and if so, does it matter, or are there multiple centers?
I talk a lot about clarity as the main weapon we have in having rational conversations about cities, design, landscape, planning, and all forms of discourse. As mentioned in an essay in Atlantis magazine from last year (focused on the definitions of landscape and urbanism) the interpretation can not be fuzzy. As I mention, we should demand:
“…a call for more clarity in writing about these terms, specifically the need for clear definitions when discussing terms. We are too loose with terminology today, and the overall impact and reach of our discussion suffers from this. Whichever way you choose to interpret and intervene the urban conditions, there needs to be shared understanding of fundamental issues, because, as I mention: “In the end, no discussion or argument (binary or otherwise) is worth much if it happening around vague language…”
So what is the clear picture, and how does the exurb fit into the discussion of city growth? We need to know what we mean by terms. A quick web search brings up a definition that falls in line with my understanding:. Webster’s defines exurb as “…a region or settlement that lies outside a city and usually beyond its suburbs and that often is inhabited chiefly by well-to-do families.” This is contrasted with suburb, again from Websters, which is variously defined as “… an outlying part of a city or town, a smaller community adjacent to or within commuting distance of a city or, the residential area on the outskirts of a city or large town.”
Without getting too far into the rabbit hole of etymology, that at least makes sense – with a heirarchy of city and non-city. Thus a city includes a suburb, but not exurb. I’m sure a more thorough accounting of definitions would yield many contradictory definitions. On that note, linked in the Grist article, is a bit more of a statistical treatment of the data is from the Urban Institute where the authors Todd Gardner and Matthew C. Marlay use the census data to compare and contrast growth from 2000-2010. One conclusion is that “… in most of the 100 largest metros, growth remains higher in the exurbs than in older, denser areas closer to the core.”
In this relationship – the exurb as i read it, is a part of the urbanized area, i.e. distinct from the suburbs but part of the city, which is contrary to the above condition. If the implication is that urbanized area = city, then it goes to show that urban growth has outpaced suburban growth, not as much from an influx of people moving out of suburban areas to the city, but rather from redefinition of what components can be considered urban. But if we take the meaning of ‘city’ to include suburb, fringe, etc. – the whole discussion changes – because we are talking not about a distinct urban/suburban divide, but a more broad urban/rural divide to make the distinction – with exurbs being part of the rural and suburbs being part of the city. Confused yet!?
Anyway, back to Gardner and Marley, where their study includes a graph, below, shows the overall breakdown – which includes the afforementioned ‘urbanized’ areas, without, from what i can find, is a clear definition of what this means (or more specifically, how urbanized is differentiated from non-urbanized). They are clear in defining some parameters for the categories. For instance, the authors mention that they use a specific definition of exurbia “… using three characteristics of the built environment: (1) housing unit density, (2) age of the housing stock, and (3) commuting links to neighboring economic centers.” The assumption being that each of these categories (high-density, moderate density, low-density, fringe, and exurban), are distinctly defined.
The graph is telling – but it’s still unclear what exurb is in relation to the city (is the city high, moderate and low density, and fringe is the suburbs). Is exurban an actual ‘urbanized’ condition? The issue of, and need for this clarity, is that the authors use it and the associated data to make a strong point about the strength and role exurban development, and it’s place in the metropolis (which again, doesn’t necessarily, mean the city!). As noted in the concluding comments:
“These results illustrate the continued importance of the exurbs. Although land-use planners, environmentalists, and others concerned about sprawl and resource use decry their very existence, it is clear that the exurbs continue to house a significant share of the metropolitan population, and in fact account for much of the metropolitan population growth over the past decade. These areas have weathered the economic storm of the Great Recession; whether they are poised to continue their amazing growth of the past decade is as yet undetermined.”
A caveat at the end of the summary mentions a bit of their methodology in definition exurbia, and also contrasts the results with another study. Their study: “… combines data from the 2000 and 2010 decennial censuses with aggregated American Community Survey (ACS) data from 2005-2009. The 2005-2009 ACS data averages to 2007, produces results roughly comparable to those using the single-year 2007 ACS data, and enables us to perform tract-level analyses for every metropolitan area. To ensure comparability across time, we used consistent census tract boundaries for all data points.”
They contrast this to a recent NY Times article by William Frey on the decline of the exurbs, noting that “… contrasting results arise in part from methodological differences. For example, our study uses census tracts as the basic geographic unit, while Frey uses counties. Also, his article includes the period from 2010 to 2011, while this commentary focuses on the previous decade.”
Methodological differences will occur, and clarity of a particular approach is a good way to parse the differences, but most folks won’t get the difference between census tract data resolution versus county level data – and to me, it shows that the two studies aren’t actually talking about the same thing when they refer to exurbs. I think it’s also a big ambiguous to relate density (as noted in the definitions of some each of these categories) with location. This also brings up issues of location theories – and the mortgage crisis diminishing the mobility of people to relocate (due to being underwater) or to locate in a more desirable location (due to inflation of housing values and lack of access to lending). But that’s a topic for another time.
It does seems to echo the clean divisions of the urban-to-rural transect, with a monocentric model of radiating density that combines both spatiality and density – each level (or ring) becoming less dense and less ‘city’.
It would be interesting to see where the distinction between the categories by Gardner and Marley ((high-density, moderate density, low-density, fringe, and exurban) relate to the T-zones of a typical urban to rural transect – and if exurb would equal T3 (suburban) or a hybrid of General Urban (T4) or be an outer version – an exclusive enclave of T2 (rural reserve)? I realize these are models and abstractions, but that should make definitions easier because they lack the messiness of reality and can be defined in concrete terms. This can translate to at least a common parlance for terms, as an idea of some shared way of discussing a city isn’t too much to ask, particularly when we are using this to develop policy and allocate resources.
A fascinating topic worth future exploration – and i hope to discuss more – with comments, as always, welcome.
As an example, King mentions the Sierra Pacific Megapolitan Area, seen below as a large geographical area that extends from the San Francisco Bay area all the way into Western Nevada, around Reno. The region includes 27 counties and includes over 12.4 million people, and its expected to grow substantially in the next 30 years.
As mentioned in the article, the significance of the concept of megapolitan areas is to look more broadly at a larger scale, King, quoting Nelson, mentions that “regions can be more proactive in everything from transportation planning to economic strategies… to have people look at things a little differently, the whole rather than the parts.”
While explicitly not a model for mega-regional government, there are some possibilities of what this might mean for regions by looking at larger areas. As mentioned by King, “It’s too early to say whether the concept of megapolitan areas will catch on as a framework for government policy, much less in terms of how regular people define where they live.”
The significant of megapolitan areas, thus is undetermined. The overall ambiguity of the defining characteristics of a ‘city’ has led to a lot of questions related to city centers, sprawl, and other hybrid urban agglomerations like edge cities, exurbs, and the shift from urban area to metropolitan statistical areas (MSAs). This leads to a lot of diversity in definition (outlined in the SF Gate article) – including the largest megapolitan area (NY-Phil 33.9 million people) to the smallest, fastest growing (Las Vegas 2.4 million). While Vegas booms, the Steel Corridor of wester PA is creeping along slowly. In terms of diversity, not surprisingly, the Southern California region has the largest percentage of minorities (62.7%) and the Twin-Cities are the least diverse with 15.5% of minorities.
The terms megaregion, megalopolis, megapolitan area, while similar in nature, are somewhat different historically, spatially, and statistically, so it is worth a look at some of the designations. A map of megaregions shows the eleven areas in the United States as determined by the Regional Plan Association.
This differs somewhat from a more recent version of Megapolitan areas from a recent essay by Lang and Nelson on Places from Design Observer) They identify 10 megapolitan clusters that exist in 23 megapolitan areas that are similar but slightly different from those above.
The different terms, definitions, and geographical extents makes the concepts a bit difficult to parse, but in general terms, the areas are defined by a population of more than 10 million people that exist within a ‘clustered network of cities’ typically delineated through transportation corridors.
The new interpretation of Megapolitan area builds on earlier concepts to describe a more general ‘transmetropolitan geography’ which is typically thought of more commonly in larger, global areas such as China, Japan, Brazil – which include megaregions of 120 million (Hong Kong, Shenzen-Guangzhou), 60 million (Nagoya-Osaka-Kyoto-Kobe) and 43 million (Rio de Janeiro-Sao Paulo). While the concepts are similar, the scale of these new global areas are immense in comparison to the US.
Interestingly enough, the term has been used since the 1820s, and the conceptual usage of the concept of Megalopolis as a grouping of urban areas within a region dates back almost 100 years. This includes references by Oswald Spengler in The Decline of the West (1918) and Lewis Mumford in The Culture of Cities (1938). The most popularized recent usage was from 1950s and 60s, in the book on the Northeast United States by Jean Gottmann entitled ‘Megalopolis’ (1961).
More on this in subsequent posts, specifically additional information on Lang and Nelson’s longer essay in Places, and a closer look at the book. Stay tuned.