One generalized truism is that European cities are walkable and transit-supportive, and North American cities are not. This is not universally true, but it's often thought to be directionally true. However, a recent paper called "Car Dependency in Urban Accessibility" reveals that this may not be as true as we think.
The study introduces something called a Car Dependency Index (or CDI). What it effectively does is compare accessibility to jobs and services within a city by car versus public transit. They did this for 18 European and North American cities, and here's what they found:
A positive score (red on the map) means that a car can access more opportunities than public transportation, and a negative score (blue on the map) means the opposite. What's not surprising is how car-dependent the outskirts of most cities are, including European cities. Car dependency was high in over 70% of the urban territories that they analyzed.
What is more surprising to me is that most cities don't have much, if any, blue. The best-case scenario seems to be a lot of white (which represents accessibility parity between cars and public transit). Hmm. Does Manhattan really not have any blue? The glaring exception is Paris and, to a lesser extent, Zurich, though keep in mind these are only city proper boundaries.
Another finding is that car dependency remains a primary driver of car ownership, even when accounting for income. What this means is that if you took two people with the exact same income, one living in transit-rich Paris and the other living in the suburbs of Rome, the person in Rome is much more likely to own a car.
Once again, this supports the obvious fact that if we design cities so that they're inconvenient to navigate without a car, well, then more people will get cars. It's not easy to build a transit network that can compete. Individual lines won't do it. The key word is "network." And you need the right land-use policies to support it.
Cover photo by Alessio Ferretti on Unsplash
Charts from "Car Dependency in Urban Accessibility."
In the olden days here in Toronto, approved development land used to sell for a premium compared to unapproved land. This was true because approved land meant you could start construction much sooner. And since time has value, this was worth something.
Today, this is far less valuable to developers (if at all) because, in most cases, the market does not support new construction. So, the land may be approved, but what does one do with it?
Rather than speed, I would say that the most valuable feature right now is the ability to be patient. Developers need to be able to stay solvent long enough for the market to return. But this does not mean that there isn't a cost to permitting, approvals, and lengthy pre-construction periods.
Here is a recent paper (that I discovered via Thesis Driven) by economists Evan Soltas (Princeton) and Jonathan Gruber (MIT) that asks: "How Costly Is Permitting in Housing Development?" What they discovered in the Los Angeles market is the following:
Developers have been willing to pay roughly 50% more for pre-approved development land (averaging about $48 per square foot).
The permitting process in Los Angeles accounts for about 40% of the time required to develop and construct a new housing project.
Approximately one-third of the gap between home prices and construction costs can be explained by permitting costs and delays.
This last point is an interesting one to focus on because it tells you how much regulatory fat there is in the system. In a perfectly free and efficient market, the market price of a home should, in theory, be roughly equal to the cost of the land, construction costs, and the developer's margin.
When you have a massive gap between the cost of the physical materials and labour required to build the home and the price of the home, it means that there are other costs being shouldered. The paper refers to some of these as "pure wait" (time) and "capitalized hassle" (dealing with bullshit).
This is an important way to think about the efficiency of housing markets, because minimizing the gap is a clear way to make housing more affordable.
Cover photo by Josh Miller on Unsplash
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