Here is an interesting study that looked at the impact of urban highways on social connections within the 50 largest US cities. To measure this, the researchers used Twitter data from 2012-2013, which is a period of time where the default setting in the mobile app was to tag each tweet with the user's precise geographic coordinates.
This allowed the team to generally figure out where a user is likely to live. If you're often tweeting from the same residential address, then there's a good chance that's home. They then looked at things like mutual followship as a measure of social ties. And what they ultimately found was that in all 50 cities, urban highways exhibit a strong barrier effect. They measured this using something they call a "barrier score."
Now this sounds right and supports lots of other evidence that highways divide cities; but Twitter isn't necessarily a place where mutual followship means you actually know the person in real life and you regularly walk down the street to see if they can come out and play. So one of the things that the researchers also did was work to replicate their findings using data from another social network called Gowalla.
I very vaguely remember this platform, but it is/was a social network where users are supposed to connect with people they actually know and share their locations through check-ins. With this data they found that their "barrier score" was even more pronounced, which makes sense given that the platform's social graph should have had, in theory, stronger real-life ties.
But even if you don't believe the social data, these results should make intuitive sense. Highway underpasses and overpasses tend not to be the best environments for pedestrians. They're usually a clear break in a city's urban fabric, which can make people second guess whether they really want or need to cross it.
Cover photo by Tom Barrett on Unsplash
Here is an excellent reason for why you may want to spend more time walking:
People have noted that walking seems to have a special relation to creativity. The philosopher Friedrich Nietzsche (1889) wrote, “All truly great thoughts are conceived by walking” (Aphorism 34). The current research puts such observations on solid footing. Four studies demonstrate that walking increases creative ideation. The effect is not simply due to the increased perceptual stimulation of moving through an environment, but rather it is due to walking. Whether one is outdoors or on a treadmill, walking improves the generation of novel yet appropriate ideas, and the effect even extends to when people sit down to do their creative work shortly after.
The results were a bit inconclusive as to whether outdoor walking is better than other forms of walking, so for now we will just say that walking -- in general -- is good for creative thinking. But where my mind immediately goes is: Does this finding scale up?
In other words, if you were to take two different cities -- City A where everybody, for the most part drives, and City B where everybody, for the most part, walks -- could you find any evidence that City B was on average more creative than City A?
I guess one way you could measure this is through patents. And if you were to look at patents per capita in the US, you'd likely find cities like Princeton (NJ), Redmond (WA), and cities in Silicon Valley near the top of the list. I'm not sure there's an obvious correlation here.
But it is kind of interesting to think about a possible relationship between urban form and creativity.
Here is a housing study that looked at housing supply -- in the US from 2000 to 2020 -- relative to median housing values. And here is the key takeaway:
What this chart is saying is that new housing is rarely added in cities with the lowest-value homes. The bar on the left represents municipalities whose median housing values are less than 50% of the metropolitan average. And this makes sense. If values are low there is likely little to no incentive to build. The math just doesn't work.
However, as home values increase, the incentive to build and the ability to finance new projects also increases, and that is what we see in the above chart. This also makes sense.
But something interesting happens in the highest-value cities -- housing supply once again starts to fall off. And it turns out that there is a bit of a sweet spot. Municipalities whose relative housing values are 110 to 130% of the metropolitan average actually produce the most overall housing. Any higher than that and things start to decline.
Why is that? The answer likely has to do with restrictive land-use regulations. The highest-value cities (and wealthiest suburbs) often have a lot of large single-family lots, as well as policies to ensure that this kind of built form doesn't change. This has the effect of both limiting supply and enshrining values.
So when it comes to housing supply, what you don't want are low-cost areas. But you also don't want the highest-value areas. What you want are areas that are doing well, but no so well that they start really restricting new entrants. This is what our industry often refers to as exclusionary zoning.
Now, one of the most common ways to respond to this problem is to develop an opposing policy, namely inclusionary zoning. But usually what this policy doesn't do is direct more supply to these high-value and low-density areas. Instead what it typically does is force the segment that is producing the most housing -- let's call it the 110 to 130% band -- to deliver more affordable housing.
It's a neat trick that sounds pretty cool, but it is not at no cost.
