Urban Sprawl

Mark Thoma's site has a link to Paul Krugman's discussion of the association between sprawl and low social mobility.  It appears that if you do a plot of urban density versus social mobility of the lowest quintile to the highest quintile you get a very surprising linear relation: as density drops it looks like persistent inequality rises.  Paul Krugman is appropriately skeptical that this is the whole story:

Is the relationship causal? You can easily think of reasons for spurious correlation: sprawl is associated with being in the sunbelt, with voting Republican, with having weak social safety net programs, etc.. Still, it’s striking.

Matt Yglesias adds additional data about what happens with kids who move into high density urban areas as well as a few other possible explanations:

So what drives this? The study does not really make a high-powered effort to draw strong causal inferences. But the study does show that kids who moved into a high-mobility area at a young age do about as well as the kids born in high-mobility areas, but kids who move as teenagers don't. So there seems to be a factor that isn't parent-driven. The authors report that tax policy, the existence and affordability of local colleges, and the level of extreme local wealth do not appear to be strong correlates of intergenerational mobility. Metro areas where the poor are geographically isolated from the middle class have less intergenerational mobility, while metro areas with more two-parents households, better elementary and high schools, and more "civic engagement" (measured through membership in religious and community groups) have more.

 So clearly it would be a mistake to over-interpret these data. But they do have one major policy piece embedded into them -- it makes absolutely no sense to subsidize sprawl as a positive good.  It may not be worth it to try and discourage it, but generally there are a lot of laws (think zoning laws and car centered transportation grids) that implicitly subsidize sub-urban communities.

There are still pieces to be considered -- like does the poorest quintile do objectively better or worse in the low social mobility environments (you can justify low mobility if everyone is better off as a result).  However, the two extremes in Paul Krugman's graph are Atlanta (low density and mobility) and Los Angeles (high density and mobility).  It's not 100% clear that it is better to be poor in California than Georgia, but it isn't like it is far worse in California so far as I can tell.  Maybe Mark can weigh in here? 

But this all points to a big picture that urban planning is actually a much bigger deal than I had previously realized. 

Utopian urbanists and the will of God

Here's a hypothetical discussion I'd like you consider, not because it could ever happen but because I think it makes an interesting thought experiment.

Imagine we're sharing a cup of coffee with Edward Glaeser and we make them the following proposal: let's take a large metropolitan area in the South or West and just zone the hell out of that puppy, set aside huge swathes of land right through the middle of the city, allow no development whatsoever, not even any roads except for a couple of elevated highways.

I predict that Glaeser would object strenuously to the suggestion. He would probably start things off by waxing eloquently on the evils of zoning, then decry the inefficiency of wasting land that could potentially house millions of city dwellers.

Suitable chastised we drop that idea and change the subject, asking him what cities in the South or West we should look to as models. I'll make a second prediction: he would cite either Seattle or San Francisco (and possibly both), praising them for their density, walkability and lack of sprawl.

The trouble is that all of these appealing aspects are pretty much a direct result of large swathes of undeveloped land that cover large parts of these area, swathes that can be driven across only by way of a handful of elevated highways.

Of course, it's awfully easy to be unfair to someone when you're writing his dialogue for him. It's quite possible that I've misrepresented Glaeser's positions on one or both of my predictions. Still, when I read Glaeser, I can't shake the impression that he's not just suggesting policy changes that can make things better; he's talking about a utopian product of libertarian ideals.Because of this I get the feeling that a city building around a body of water is fundamentally different than a city building around a piece of zoned land, even if the end result is the same. (Is it even possible for the end result to be the same? That's a topic for another post)

None of this makes Glaeser's analyses bad or diminishes any of his many good ideas, but when it comes to setting policy, utopianists always make me nervous.

California Falling

In interesting news today, California is now at the very bottom of the top ten states for wealth. The continued prosperity of the East Coast is beginning to look a lot like a strong argument for density. Density has historically been a critical way of bringing ideas together. For a while it looked like California was an attempt to show how prosperity could work with lower density population patterns.

We'll see if this is a trend or an isolated blip, but it doesn't bode well for the West Coast pattern of settlement.

Another New Haven thought

Matt Yglesias wonders if looking at just New Haven alone is the wrong unit of analysis as the surrounding county is quite prosperous. I think that this quote nicely summarizes the problem with this analysis:

But even the strongest cities can't -- and shouldn't have to -- handle the costs of urban poverty by themselves/ In the 1960s and 1970s, rich and middle-class city dwellers fled to the suburbs in part to escape having to pay the costs of addressing urban inequality. Rich enclaves have often formed right outside of urban political boundaries, where the prosperous can be close to the city without having to pay its taxes or attend its schools. A level playing field mans that people should be choosing where to live based on their desires for neighborhood or opportunity, not based on where they can avoid paying for the poor.

-- Edward Glaeser, Triumph of the City, page 258.

The difference between Seattle and New Haven is that the core of Seattle had managed to capture at least part of the prosperity that comes from institutions like the University of Washington and Microsoft. This suggests to me that there is at least a two stage process to using a university to enhance urban prosperity.

It also suggests we might want to be leery about things like significant budget cuts as it would be foolish to risk disrupting these types of success stories.

Credit where credit is due

I have resumed reading Edward Glaeser's book Triumph of the City. I am not always a fan of Dr. Glaeser's arguments but his discussion of urban sprawl is interesting, perceptive, and (I suspect) correct. The section is worth it for the discussion of Paris and alternative models of urban density alone.

I am not convinced that he has modeled the predictors of urban prosperity well but I find his arguments for the drivers of sprawl to be compelling. I would be skeptical of any attempt to seriously engage the problem that did not consider these points. For example he references a fixed time cost to public transportation (waiting for the bus, traveling between destinations and stops) that puts the focus on car use in a whole different light.

I was back to being impressed with his work in this section.