Tuesday, January 04, 2011

A Physicist Solves the City (and implications for density vs mobility)

There's been a buzz lately about this NYT piece on Geoffrey West (not all of it good - scroll down to the second section).  He applies some complexity principles to cities, which yields some interesting insights, albeit ones we kinda already knew.

I highly recommend reading the whole thing, but here are some excerpts that jumped out at me:
He didn’t want to be constrained by the old methods of social science, and he had little patience for the unconstrained speculations of architects. (West considers urban theory to be a field without principles, comparing it to physics before Kepler pioneered the laws of planetary motion in the 17th century.)
...all of these urban variables could be described by a few exquisitely simple equations. For example, if they know the population of a metropolitan area in a given country, they can estimate, with approximately 85 percent accuracy, its average income and the dimensions of its sewer system. These are the laws, they say, that automatically emerge whenever people “agglomerate,” cramming themselves into apartment buildings and subway cars. It doesn’t matter if the place is Manhattan or Manhattan, Kan.: the urban patterns remain the same. West isn’t shy about describing the magnitude of this accomplishment. “What we found are the constants that describe every city,” he says. “I can take these laws and make precise predictions about the number of violent crimes and the surface area of roads in a city in Japan with 200,000 people. I don’t know anything about this city or even where it is or its history, but I can tell you all about it. And the reason I can do that is because every city is really the same.”
In city after city, the indicators of urban “metabolism,” like the number of gas stations or the total surface area of roads, showed that when a city doubles in size, it requires an increase in resources of only 85 percent. (which is part of why growth is good)
...modern cities are the real centers of sustainability... Small communities might look green, but they consume a disproportionate amount of everything.
In essence, they arrive at the sensible conclusion that cities are valuable because they facilitate human interactions, as people crammed into a few square miles exchange ideas and start collaborations.
According to the data, whenever a city doubles in size, every measure of economic activity, from construction spending to the amount of bank deposits, increases by approximately 15 percent per capita. It doesn’t matter how big the city is; the law remains the same. “This remarkable equation is why people move to the big city,” West says. “Because you can take the same person, and if you just move them to a city that’s twice as big, then all of a sudden they’ll do 15 percent more of everything that we can measure. ...when people come together, they become much more productive.”
Consider the data: When Bettencourt and West analyzed the negative variables of urban life, like crime and disease, they discovered that the exact same mathematical equation applied. After a city doubles in size, it also experiences a 15 percent per capita increase in violent crimes, traffic and AIDS cases. (Of course, these trends are only true in general. Some cities can bend the equations with additional cops or strict pollution regulations.) “What this tells you is that you can’t get the economic growth without a parallel growth in the spread of things we don’t want,” Bettencourt says. “When you double the population, everything that’s related to the social network goes up by the same percentage.”
...the positive feedback loop of urban life — a growing city makes everyone in that city more productive, which encourages more people to move to the city, and so on. According to West, these superlinear patterns demonstrate why cities are one of the single most important inventions in human history. They are the idea, he says, that enabled our economic potential and unleashed our ingenuity. ...As cities get bigger, everything starts accelerating.
The only real criticism I have is the leap from "interactions are good" to Jane Jacobs' "we need density so we can run into each other on the sidewalk."  Yes, all through history up until about 50 years ago, density was the best way to increase interactions.  But now we have a wealthy society where just about everybody owns a car.  It's no longer about unplanned interactions on the street or planned interactions we walk to, but planned interactions that we drive to.  That shifts the focus from density to mobility: what parts of town can I reach in a reasonable time?  That will dictate what events/interactions I attend vs. don't because it takes too long to get to them.  That means business meetings, restaurant meals, and social, entertainment, and networking events of all types - if they're too much of a hassle (i.e. time, distance, traffic, parking), I'm probably not going to do them.

To repeat what I've said before on this blog: in Jane Jacobs' old world, mobility was fixed (i.e. walking speed) and density was variable, so maximize density - vs. today's world where density is constrained to a relatively modest range (to accommodate cars and a more affluent peoples' desire for more private space (historical norms of large families in small apartments vs. today with singles and couples in large apartments and small families in large houses)) but mobility is variable depending on freeway and arterial networks vs. traffic congestion.  Developing a few dense neighborhoods to meet demand is fine, but the real bang for Houston's buck is improving mobility - and therefore interactions - for all.

(Hat tip to Howard for the heads up on the article)

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At 10:33 PM, January 04, 2011, Blogger Jardinero1 said...

I don't run into many people on the sidewalk but I sure run into a lot of people on the phone and internet and e-mail and texting. Probably more people in a day than the typical fast moving New Yorker did back in the thirties. I do this in un-dense Houston which is still smaller and less dense than New York in the thirties.

At 9:21 AM, January 05, 2011, Anonymous Stephen Goldsmith said...

Jane Jacobs observations about running into people on the sidewalk is more complex than reducing the idea to a discussion of mobility. Destinations where meeting-up with someone we already know limits the possibility of discovery along the way, the process of moving through the city vs. the destination.

Improving mobility, even if we could click our heels or rub our nose and get to our destination does not account for the importance of "running into" people we don't know, and removes the opportunity for growth and discovery. The same is true even with our new technologies; texting and email occurs among people we already know, whereas "running into" people along our journey who we don't know has the added dimension that can lead to something new, like a good idea, or seeing something that delights us, changes our mood, adds to our creative process. This is much more complicated than how we arrive at destinations. It is about how we discover life's unfolding opportunities as we move through time and space.

At 9:38 AM, January 05, 2011, Blogger Tory Gattis said...

While I'll agree that there is a neat feel to walking through a crowded district, you can certainly discover new places as you drive past them to some other destination, and then get back to them later. We also have technologies for meeting new people, like via Facebook, Twitter, or, ahem, blogging. And I'm convinced that 99% of our "new social interactions/discoveries" occur at events, restaurants, coffee shops, or places we specifically attend, not along sidewalks, even in NYC.

At 12:53 PM, January 07, 2011, Anonymous Anonymous said...


Paul Krugman doesn't like Texas.

Care to compose a rejoinder, Tory?

At 1:36 PM, January 07, 2011, Blogger Tory Gattis said...

Yep, I saw that this morning. I don't really get his point. The bad economy was going to cut state revenues no matter what. Is he saying we'd be better off if we had a fat govt with easy cuts, instead of a lean govt with tough cuts?

At 4:48 PM, January 07, 2011, Blogger Alon Levy said...

Krugman's saying that Texas is doing about as well as New York, so conservatives should stop pointing to it as a special small-government success.

At 9:04 PM, January 07, 2011, Blogger Tory Gattis said...

Well, if you measure govt by deficit, maybe so. But NY is losing two Congressmen worth of population, while TX is adding four. TX has a lower tax burden, and now has more F500 HQs. And NY is also dominated by the world's most profitable industry, finance, which was just massively bailed out by the federal govt. How come I'm not surprised they're holding up pretty well?

At 9:59 PM, January 07, 2011, Blogger Alon Levy said...

First, Texas's higher population growth doesn't mean its per capita economic pain is low. The tax level and the Fortune 500 headquarters are a policy input, chosen to generate good output.

Second, within New York State, Upstate has done better than Downstate. Finance hasn't done too well; non-auto manufacturing has.

And third, Michigan got a bailout, too. I'm not sure how much of the $18 billion the government injected into GM and Chrysler it got back, but of the finance bailout, all but $12 billion (all coming from AIG) were recovered as the banks' stocks went up.

At 10:06 PM, January 07, 2011, Blogger Tory Gattis said...

TX suffers when the nation suffers, just like Europe's troubles plague Germany, even though most acknowledge that the German's have the most sound fundamentals - as TX does in the US.

Finance in metro NYC (inc NJ and CT) is a massively bigger deal than the relatively weak upstate NY. Financial companies represent almost 1/3 of all S&P500 profits. The top 25 hedge fund managers make more money than all S&P500 CEOs combined. If the banks had been truly allowed to fail, NYC - and all of NY - would be a total basket case right now on par with Nevada and Vegas.

The auto industry bailout went to the bondholders (i.e. the banks), not to the state of Michigan. GM and Chrysler have had massive layoffs and factory shutdowns. They're healthier now, but also much, much smaller.

At 8:24 PM, January 08, 2011, Blogger Michael said...

>>But NY is losing two Congressmen worth of population, while TX is adding four. TX has a lower tax burden, and now has more F500 HQs

I think you need to look at these sorts of things over the long term - as in - decades. As Krugman said, the $25 billion budget deficit in Texas hasn't even been publicized until very recently. You would have said California real estate was looking super in 2006.

The point is - if Texas is going to respond by simply gutting its public sector, then things are going to get ugly. And then it will be Utah or Oregon or somewhere else gaining some representatives at our expense in 2020 or 2030.

Texas is blessed by several great factors - economic, cultural, location, size, natural resources. Our predominantly conservative ideology isn't something that has helped, nor is it going to help in the future.

But - this is sure going to be fun to watch Perry and other Republicans come up with answers without enraging nearly everyone between now and 2012. That's a tight-rope I'm glad I'm not walking!!

At 8:34 PM, January 08, 2011, Blogger Michael said...

>>Is he saying we'd be better off if we had a fat govt with easy cuts, instead of a lean govt with tough cuts?

Oh - and I think the point is - a moderate government would not look at this just in terms of cuts. They would look at a combination of raising revenues and cuts. Or maybe even just raising revenues. In Texas, raising revenues is pretty much out of the question. But if you want to know how a Democrat would be governing Texas right now - look at what Bill Hobby said in the Chron last weekend - $12.5 billion of increased revenue + $12.5 billion of cuts would be his approach. Perry's answer is probably going to be much closer to $25 billion worth of cuts. What else can you do when you believe that "lower taxes" is ALWAYS the right answer?

At 10:23 PM, January 08, 2011, Blogger Tory Gattis said...

Here's looking at TX over decades, from the WSJ today:


Finally there is Texas. In 1930 there were (rounded off) six million people in the Lone Star State versus 13 million in New York. In 1970 there were 11 million in Texas and 18 million in New York: Each had grown by about five million. But in 2010 there were 25 million in Texas and 19 million in New York.

Back in the 1930-70 period, liberal political scientists hoped and expected that America would become less like Texas and more like New York, with bigger government, higher taxes and more unions. In one important respect—the abolition of legally enforced racial segregation—that has happened. But otherwise Americans have been voting with their feet for the Texas model, with its low tax rates, light regulation and openness to new businesses and enterprises.

Today one out of 12 Americans lives in Texas—the same proportion that lived in New York City in 1930. Metropolitan Dallas and metropolitan Houston, with about six million people each, threaten to overtake our fourth largest metro area, San Francisco Bay (population about seven million), in the next decade.

At 10:26 PM, January 08, 2011, Blogger Tory Gattis said...

So when a recession hits, a private business doesn't have the option of raising revenues - they must cut costs - and then they grow back as their revenues allow. Why shouldn't the public sector do the same? The problem is that they jack up tax revenues to cover temporary shortfalls, and then don't bother to ratchet them back when the crisis has passed.

At 10:46 PM, January 08, 2011, Blogger Michael said...

>>But otherwise Americans have been voting with their feet for the Texas model, with its low tax rates, light regulation and openness to new businesses and enterprises.

I think this is a gross oversimplification of what is happening. And I think 90% of our growth is due to immigration - both legal and otherwise. Yes - people are migrating to where there are jobs, but if you want to look at that on a global basis, that is not even Texas anymore - that is China, India, or other developing nations. The US growth rate from 2000-2010 was a paltry 9.7%. Other countries are booming by comparison.

And if people are voting with their feet, then nearly 120 million people live in the pretty "high" regulation states of California, New York, Pennsylvania, Illinois, etc. By far most people who vote with their feet vote to stay where they already are.

Finally, this ignores the point that if we are to look at several decades, then Texas's problems may just be getting started - such as our $25 billion deficit, our horrible education system and environmental records, our lack of quality mass transportation, etc. etc. California was A-OK from the Gold Rush through the 1980's or so, right? No doubt Texas will continue to grow because of the other advantages that I mentioned - the question is are we going to tackle the problems we face and truly grow to be a model state / civilization, or just keep cutting taxes and building toll roads because that is what the right-wing wants.

>>So when a recession hits, a private business doesn't have the option of raising revenues - they must cut costs - and then they grow back as their revenues allow. Why shouldn't the public sector do the same?

The problem with modern conservative ideology is that there is never a time for "raising revenues". And aside from that of course private businesses have the option of raising revenues. They innovate, change their product lineup, raise prices on some products, lower them on others, etc. Look at Apple - they were left for dead in the early 1990's. Did they lay off their entire R&D staff? No - they doubled-down, and look where they are today.

Finally, private enterprise has very little to do with government - they are completely separate entities with very different options at their disposal. And it would be the definition of foolishness not to consider all options at one's disposal.

At 11:23 PM, January 08, 2011, Blogger Michael said...

>>they must cut costs - and then they grow back as their revenues allow. Why shouldn't the public sector do the same?

I guess the main reason is because generally, what the public sector does is too vital to our own well-being to make cuts in many cases. Case in point - we are going through tough times, but the citizens of Houston voted for Prop 1 - essentially to increase their taxes and raise revenues, to help pay for better infrastructure and drainage around the city. It seems like the conservative answer to the drainage problem would be some sort of Mad Max answer where everyone pays for their own drainage system, buys a canoe, or moves out of town. Fortunately the citizens of Houston are smarter than that and realize that sometimes, the right answer is to raise revenues and solve the problems at hand. The same goes for environmental, education, transportation, and other issues on down the line.

I fear our leaders in Austin are not as intelligent as the voters of Houston. Or Paul Krugman, for that matter.

My points aside - do you have $25 billion worth of Texas state spending cuts in mind Tory?

At 8:56 AM, January 09, 2011, Blogger Tory Gattis said...

Well, in the democratic Prop 1 spirit, didn't an overwhelming number of Texans just vote in legislative reps that promised spending cuts instead of tax increases?

I'm no budget expert, but I think the right answer is probably across-the-board single-digit percentage pay cuts for all public employees, plus public employee pension reform to reduce the contributions required. There's no reason public employees shouldn't have to make the same sacrifices private ones are making.

At 9:50 AM, January 09, 2011, Blogger Michael said...

>>Well, in the democratic Prop 1 spirit, didn't an overwhelming number of Texans just vote in legislative reps that promised spending cuts instead of tax increases?

Sure - they did. And there you have the problem with Texas. But if you look at the big cities, including Houston, I don't think they are nearly as on board with this sort of agenda as the rural areas and extremely conservative areas of the state. And they vote for many of the D members of the Texas House and Senate.

And I think it is much easier to say you support cuts in the abstract, than when someone says "we are cutting support for our state universities and cutting 2000 professors and our research endowments", etc. I sure don't think that sort of thing would be / will be popular among most Houston voters.

As I said - it will be interesting to see what the R's do. What plays well in Waco is not going to make the people of the Texas Triangle happy IMHO. And it's not good for Texas.

>>I'm no budget expert, but I think the right answer is probably across-the-board single-digit percentage pay cuts for all public employees

Yeah - I'm no expert either, and I'm sure some cuts will be made. But if it comes out to $25 billion I think that's going to be a very painful pill to take.

At 4:46 AM, January 12, 2011, Anonymous Mike said...

I guess my problem with the Republican philosophy (and I have voted Republican in the last three presidential elections) is that one wonders how or when public spending is a good idea. The whole agenda seems to be, simply, "less public spending." If Republicans were to design a society from scratch, would there be any public spending at all? Would there be public funding for higher education? For lower education? Would there be public parks? Public libraries? Public resources of any kind? Or are all these things 'socialism'? At that point it seems like you basically end up with Argentina or something similar.

At 8:27 AM, January 12, 2011, Blogger Tory Gattis said...

Yes, I believe there would be all those things. My interpretation of the Republican philosophy is that govt has to do what it can within a reasonable footprint of GDP (because every dollar going to govt is one less dollar stimulating the private sector to provide jobs and productivity improvements), and that its current footprint of almost half of GDP (federal + state + local) is too much, as is the unsustainable trajectory of entitlements.

At 6:38 PM, January 12, 2011, Blogger Alon Levy said...

Pre-recession, total government spending was about 32% of GDP in the US - up from 28% in 2000, before Bush started to cut taxes and raise spending.

At 2:09 PM, January 13, 2011, Blogger Tory Gattis said...

I think that's federal only. When state and local are included, I think it gets closer to half.

At 5:09 PM, January 13, 2011, Blogger Alon Levy said...

It's federal plus state plus local. Pre-recession, federal spending was $2.9 trillion (link), which was about 22% of GDP.

At 5:22 PM, January 13, 2011, Blogger Tory Gattis said...

Then I stand corrected. Not sure where I saw the half number, or what might have been included in that.


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