One of the fundamental principles that we espouse on this blog is that land use and transportation planning are integral to one another. This matters if you're trying to build a big, bad global city because there are limits to what you can accomplish with car-oriented planning. Eventually traffic congestion becomes unbearable and the model starts to breakdown (consider Toronto and Atlanta right now).

This means that, if you'd like to continue scaling, eventually you'll need to start getting serious about transit-oriented development and other forms of mobility. Japan is one of the best examples of this. But the key prerequisite for this is urban density. This is the unlock that makes transit practical and convenient for people.

That's why this week's planning announcement is a big one for Toronto. On August 15, the Government of Ontario (through the Ministry of Municipal Affairs and Housing) approved, with some modifications, 120 Major Transit Station Areas and Protected Major Transit Station Areas in the City of Toronto. Here's a summary of the MMAH's decision via the City's website, and below is a map of the transit station areas. (Note that some station areas are missing from this map and are still under review.)

At a high level, these are areas that fall within an approximately 500-800 meter radius of transit stations, and would therefore be less than a 10-minute walk for most people. It's land that is best suited to transit-oriented development and that would strengthen any new/existing transit investments. For example, if you have an existing station that is underperforming from a ridership standpoint, the best solution is more density within its immediate catchment area.

Because of this, Ontario's Provincial Planning Statement prescribes the following minimum density targets for MTSAs:

• 200 residents and jobs per hectare for subways

• 160 residents and jobs per hectare for light rail or bus rapid transit

• 150 residents and jobs per hectare for commuter or regional rail

And to satisfy these requirements, cities need to demonstrate how they have planned for these minimum targets.

PMTSAs are a subset of MTSAs and come with some additional features, such as minimum unit counts and/or floor space indexes (floor area ratios). These are also the only transit areas where cities have the option of enabling Inclusionary Zoning, which is something they may do when the market rents in an area are high enough that the subsidies required to build affordable housing can be shifted onto the tenants paying market rents. (My views on inclusionary zoning can be found, here.)

Over the coming weeks, everyone in the industry is going to be analyzing the implications of this new approval. Overland (which is a legal firm that we work with) just posted on their blog that their review is underway and that they'll be posting something shortly. But in the meantime, I'd like to say that this is meaningful progress (and one that has been a longtime coming).

It acknowledges the important link between land use planning and mobility, and it better aligns our policies to support a post-car city. Of course, in many ways, this is an obvious thing to do. I started this post by calling it a fundamental principle of city building. But city planning happens slowly and incrementally. If you're following along, you'll see that Toronto is in fact growing up as a big, bad global city.

Cover photo by Andrii Khrystian on Unsplash

The Wall Street Journal recently published an article called, "Atlanta's Growth Streak Has Come to an End." It's behind a paywall, though, so I don't actually know what it says. But Paul Krugman did write about it, here, and I do know that one of the key statistics that you should know is this: For the first time since the data was collected, net domestic migration to Atlanta has turned slightly negative.

Overall, the metro area is still growing because of natural births and international migration, but it's still noteworthy that more Americans are leaving Atlanta than moving there. Because up until recently, Atlanta was a high-growth metro region. It's an important logistics hub and it has had an elastic housing supply model. That is, it used suburban sprawl to keep home prices in check.

But that is starting to change. Housing supply is dropping and traffic congestion has become one of the worst in the US. Paul Krugman hypothesizes that this is an example of "the limits of sprawl." And I would agree with this. Sprawling cities have the advantage of being able to grow quickly when they're relatively small. But eventually, they reach a population and geographic limit where the model starts to fail.

The Atlanta urban region is massive. As defined by the US Census Bureau, it is 6,612.4 km2. The only urban region that is bigger is the one around New York City. Los Angeles — which might come to mind as another large car-oriented metro region — is smaller. It's about 4,239.4 km2, but with ~2.4x the population of Atlanta.

It may also surprise you to learn that Los Angeles is remarkably dense. When looking at the entire built-up urban area, it's the densest in the US at 2,886.6 people per km2; whereas Atlanta is one of the least dense big city regions at 771.3 people per km2. This figure really stands out when you compare it to its peers, which means it's going to be that much harder for it to overcome the limits of sprawl.

Density is the unlock that allows you to get people onto trains.

The 15-minute city is a popular topic these days. So here is a recent study that used GPS data from 40 million US mobile phones to estimate the percentage of consumption-related trips that actually adhere to this concept. The unsurprising result:

The overwhelming majority of Americans have never experienced anything resembling a 15-minute city. The median resident, we found, makes only 14% of their consumption trips within a 15-minute walking radius.

There is, of course, regional variation. For New York City, the data suggests that 42% of consumption-related trips occur within a 15-minute walking radius. Whereas in more sprawling cities like Atlanta, it's only 10% of trips. Again, this is not surprising. But it begs the question: What should we do?

The challenge is that 15-minute cities generally require built environments that are dense, conducive to walking, and filled with a concentration of different amenities. And this is more or less the opposite of the prototypical suburban model, where the car and single-use zoning tends to spread everything out.

The good news is that zoning is relatively easy to change. For instance, if we want to allow corner stores in our residential neighborhoods, that is a decision we can make. The greater hurdle will be transforming car-oriented communities into places where people might actually want to walk. This is much more difficult.

But of course, it too can be done.