Friday, April 6th, 2012

Census Bureau Releases Latest Take on America’s Urban Areas

We are used to dealing with jurisdictional boundaries when assessing and comparing cities. These are often either municipal areas or metropolitan statistical areas (which are based on entire counties). But these can have little relevance to the amount of area in a given city-region that is actually urban in nature. This makes apples to apples across regions difficult.

Once a decade though the Census Bureau gives us a more detailed look. They release definitions of so-called “urbanized areas” that attempt to look at just the amount of land that is actually urban in form. In theory this would allow for better apples to apples comparisons between regions. Unfortunately, most data is not sliced this way, so we only get this glimpse. Here’s the map of the new 2010 urbanized area definitions:

Wendell Cox has a breakdown of the largest urbanized areas that includes density. He also published a historical review that tracks urbanized area population and density since 1950 for the largest city regions. For more thoughts on urbanized areas, see Nate Berg’s take over at Atlantic Cities.

I don’t want to try to offer a complete analysis of this right now, but one thing that really jumped out at me was the very low densities of some southern boomtowns like Atlanta (1,707/sq. mi) and Charlotte (1,685/sq. mi.). Contrast with even Houston (2,979/sq. mi.) and Dallas (2,879/sq. mi) and see the difference. Atlanta is already showing serious signs of weakness vs. the Texas mega-metros and I wonder if this is part of the reason why. It also makes me wonder if Charlotte might someday suffer in a similar manner if its growth ever flames out.

Topics: Demographic Analysis

13 Responses to “Census Bureau Releases Latest Take on America’s Urban Areas”

  1. Andy says:

    While I’d like to agree with you about UA density as a partial factor in the strength or weakness, a glance at the data in Cox’s chart does not suggest much of a correlation. Pittsburgh’s UA is also very low density; LA has much higher UA density than New York. Las Vegas and Phoenix have higher UA density than I’d expect.

    I imagine this calls for some regression analysis.

  2. Andy says:

    … which is why the caveat “I don’t want to try to offer a complete analysis of this right now” was a prudent one.

  3. John Morris says:

    In spite of all the official denial of it’s existence, it looks like Pittsburgh and Cleveland pretty much share one urban cluster.

  4. Derek Rutherford says:

    We need to be careful about the density figure, as it is heavily influenced by the terrain of the suburban areas.

    The TX cities (DFW, Houston) and LA are largely flat and the suburban development doesn’t leave a lot of “gap” areas within the metro area. Cities like Atlanta and Boston have lots of hills/small mountains within the suburban areas, which results in big green areas without development. While this is arguably a positive amenity, it results in lower density and can lengthen commutes. As examples, look up the Middlesex Fells (NW of Boston) and Morningside Nature Preserve (nr Atlanta). DFW, Houston and LA simply don’t have comparable areas within the metro boundaries.

  5. Alon Levy says:

    Here is a ranking of major cities by weighted density.

    Atlanta is indeed unusually low-density. But beyond that, I don’t really see the correlation between density and growth. Pittsburgh is one of the least dense metros, but grew very fast. Houston and Portland have nearly the same weighted densities, but one grew fast and the other didn’t. San Francisco and San Jose, both dense, each had negative income growth.

  6. John Morris says:

    I think Pittsburgh was pretty dense during it’s growth phase.

    Anyway, geography is the biggest single factor at work, making these stats pretty meaningless.

    I don’t mean totally meaningless, but one has to do a lot of digging and connecting to end up with much.

  7. Chris Barnett says:

    Derek, you might want to check out LA. It is most assuredly not flat, and neither are its suburbs, and both contain really rugged mountain/canyon areas. None of the Eastern cities you mention have the kind of dramatic elevation changes (and unbuildable areas) that the LA Metro does.

    Look at aerials of the vast tracts from Dodger Stadium west through Griffith Park, along Mulholland Drive west to Topanga Canyon and Malibu; the Baldiwn Hills; the Palos Verdes Peninsula; and the large wilderness area between Laguna Beach and Irvine. Look at the triangle formed by the Foothill, Glendale, and Ventura Freeways. And that doesn’t get into the adjacent Riverside-San Bernardino metro, which is really part of a single LA megapolitan area.

    From Wikipedia:

    “[The City of]Los Angeles is both flat and hilly. The highest point in the city is 5,074 ft (1,547 m) Mount Lukens, located at the northeastern end of the San Fernando Valley.”

    Obviously the lowest point is sea level. That’s almost a vertical mile within city limits over a distance of 30 miles or so.

  8. Derek Rutherford says:


    You raise a fair point (my travel to LA has always been to the flat parts). When LA’s urban area is calculated, do they include the rough areas you list, or not? The areas you are referring to are so large that they might not be included in the figures shown.

    I agree with John Morris that these density figures are of very little use due to terrain differences and questions regarding which boundaries to use for each urban area.

    Also, when urbanists refer to “density”, they usually only mean the density of downtown area. I rarely hear urbanists express strong opinions about suburban density unless it is in the immediate vicinity of a train station. Has anyone ever heard an urbanist compliment LA, DFW or Houston for having denser suburbs than Boston and NY? These metro area figures are dominated by the density of the suburbs, not the downtowns (NY may be an exception here).

  9. Mike Hicks says:

    Austin Contrarian went through the exercise of calculating weighted densities for a bunch of metropolitan areas a few years back. That does a much better job of matching perceptions, in my opinion. It should be repeated with 2010 data.

  10. John Morris says:

    Wow, the weighted density numbers actually look and feel right and very useful!

  11. Eric O says:

    I’m used to laying out developments in Charlotte, NC, so I can give you a few thoughts as to why Charlotte has such low density. Whenever I hover over Western/Southwestern U.S. cities on Google Earth, studying patterns of new development over there, I often gawk at the enormous building coverages Western subdivisions achieve. LA’s cheek-and-jowl compactness in single-family and courtyard apartment blocks is… just alien to me. The baseline expectations for development are simply different between both cultures (and, yes, they are different building cultures). One pertinent example: in Charlotte, single-family lot depths tend to stay around 150 feet deep, in the new subdivisions of the Southwest, 100-foot deep lots are common. But more than anything, those subdivisions are extremely compact and jammed tightly against each other, leaving very few “gaps” in the fabric. In Charlotte, we tend to preserve a lot of green space, both in and around our developments, in order to preserve as much existing tree cover, stream zones, etc. as we can. As a result our development simply thins out comparatively over the region.

    This past decade, new subdivisions in Charlotte have adopted some of the compact qualities of Traditional Neighborhood Developments, but the effect of this has been to simply develop in tighter clusters, limiting imperviousness, while preserving great swaths of natural area. We simply build New Urbanist “pods”, really TND cul-de-sacs, in nature now. What’s more our “Corridors and Wedges” growth policy encourages this, relegating higher density to limited “Corridors” and ensuring that suburban densities in the “Wedge” areas stay where they are or even get worse. While Charlotte has achieved much lauded success with TOD development along its new light-rail corridor, the progressive completion of the I-485 loop, which serves “wedge” growth of immense scale, has been a far more potent catalyst to development. It is thus no surprise that our overall density has fallen from 10 years ago.

  12. Cltplanr says:

    Yet Charlotte is blessed with timing– having not sprawled too much pre-recession, yet continuing to attract Gen-Y and Baby-Boom households now seeking urban lifestyles post-corrrection.

    And since Charlotte never had much “old urbanism” to begin with (save a limited, one-mile ring of “streetcar suburb” neighborhoods just outside its shiny CBD), its pent-up demand for urban housing has now fueled the East Coast’s largest apartment boom (as share of total building permits).

  13. Robert Hurst says:

    Texas metros are strong currently because of the boom in tight oil and tight gas production.

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