In may ways, this recent article by Brian Potter about how fast cities can grow, feels intuitive: Small cities tend to grow faster than big cities (on a percentage basis) and, as cities get bigger, their growth rates tend to decline. It is, however, still interesting to see the data behind this intuition:
A city of less than 100,000 might be able to have growth rates of 10-20% or more, and cities of up to 3-400,000 can potentially have growth rates in the neighborhood of 10-15%. Potential growth rates tend to fall as cities grow larger, and cities above 1 million people almost all grow at less than 10% per year, and usually less than 5% per year. The US, the Middle East, Southeast Asia, Africa, and South America all seem to have followed this basic pattern, assuming the data is reliable.
It is also a good reminder just how much of an outlier China is:
Unsurprisingly, since 1950, Chinese cities have mostly exhibited higher growth rates than US cities. Only around 12% of US data points are above a 5% growth rate, whereas for China this is close to 50%. China also has 2.5x the fraction of cities growing above 10% per year, and 3.3x the fraction of cities growing above 15% per year.
And some cities are outliers even within China. The most notable here is
In may ways, this recent article by Brian Potter about how fast cities can grow, feels intuitive: Small cities tend to grow faster than big cities (on a percentage basis) and, as cities get bigger, their growth rates tend to decline. It is, however, still interesting to see the data behind this intuition:
A city of less than 100,000 might be able to have growth rates of 10-20% or more, and cities of up to 3-400,000 can potentially have growth rates in the neighborhood of 10-15%. Potential growth rates tend to fall as cities grow larger, and cities above 1 million people almost all grow at less than 10% per year, and usually less than 5% per year. The US, the Middle East, Southeast Asia, Africa, and South America all seem to have followed this basic pattern, assuming the data is reliable.
It is also a good reminder just how much of an outlier China is:
Unsurprisingly, since 1950, Chinese cities have mostly exhibited higher growth rates than US cities. Only around 12% of US data points are above a 5% growth rate, whereas for China this is close to 50%. China also has 2.5x the fraction of cities growing above 10% per year, and 3.3x the fraction of cities growing above 15% per year.
And some cities are outliers even within China. The most notable here is
, which saw enormous growth after it became China’s first special economic zone in 1980. At a population of around 200,000, Shenzhen was growing at 35% annually, and it was still growing at over 20% annually when its population crossed 2 million.
Just imagine these numbers compounded. Even small variances can result in significantly different outcomes over time:
New York’s growth rate, however, declined less than Los Angeles or Chicago as the city grew larger. At around 3.5 million people, New York was still growing at over 3% per year, compared to less than 1% for LA and Chicago. This may not sound like much, but it's the difference between doubling in size every 23 years vs. every 70 years.
Now here's what I'm wondering after reading the article: Should we be thinking of city size as the single most important factor in determining urban growth? Because my mind immediately went to population densities, zoning controls, and other factors that might constrain or encourage growth.
But the data seems to suggest that, for many cities, this doesn't seem to matter over the long run. It is as simple as saying, "this city has X number of people and so it's more than likely growing at somewhere around Y% per year."
That said, what's up with China? What is it that allows a city of 2 million people to still grow at over 20%? Is it the sheer influx of people migrating from rural to urban areas? Or is it that you need a one-party authoritarian state to really clear the way for growth?
As cities get bigger there does appear to be a natural tendency toward slower growth. Part of this is the low base effect. But the declines are not always consistent and there are meaningful outliers. I am now curious to know what, for the most part, causes these differences.
As an add-on to yesterday's post about ground floor retail in mixed-use developments, I thought I would provide a few illustrative and real-world examples to demonstrate some of the challenges that I was trying to describe.
Note that this post is not meant to be critical of any specific projects; instead, it's intended to further explain some of the challenges facing developers, architects, policy makers, and everyone else involved in the built environment.
Let's start in Toronto. Below is an aerial photo of Ossington Avenue. For those of you who aren't familiar, this is one of the most desirable and coolest main streets in city. I mean, check out this recently completed office/retail building at 12 Ossington by Hullmark.
Earlier this year, Salt Lake City enacted new policy called the Downtown Heights and Street Activation Ordinance. As the name suggests, the ordinance addresses building heights, allows for taller buildings in the city, and works to improve ground floor animation. This is among other things.
We all recognize that blank walls (at street level) are suboptimal for urban vibrancy. But the thing about retail is that it doesn't work everywhere. Even if we really want it everywhere, that may not be possible, at least in the short-term. Retail is usually a lagging indicator. The demand typically needs to be already in place for it to do well.
That said, in really central areas, the correct decision could be to just mandate it everywhere. And that is what SLC has done in its central business district:
However, things get trickier in transitional or emerging areas where you're kind of just hoping that retail might someday work. From a development perspective, if we weren't convinced that the retail would work and if we were being forced to build it, we would underwrite it very conservatively. This might mean applying zero (or even negative) value to it. This way if we can't lease the space and it remains empty, at least it isn't fatal. But it does mean that the rest of the project needs to carry this loss.
Of course, now you still have a ground floor animation problem. You have empty storefronts. Though one argument might be that at least you've provisioned for a future where retail does eventually work. And if this does happen, then somebody was clairvoyant and you're happy that you built it. But if the area doesn't ever support good retail, well then you're stuck with an underperforming ground floor.
One alternative solution that can work on non-obvious retail streets is live/work. This way you build in some flexibility for the spaces to move toward retail (or other non-residential uses) if/when it becomes viable. But it's not a perfect solution. It's hard to make live/work suites entirely interchangeable. The ideal design parameters for retail are usually different than that of a home. Still, it can work reasonably well and provide needed flexibility.
It’s all very tricky. But at the end of the day, I think we can all agree that the objective is to limit blank and non-active faces on our principal urban streets. How we do that is the question. And sometimes it's more art than science.
, which saw enormous growth after it became China’s first special economic zone in 1980. At a population of around 200,000, Shenzhen was growing at 35% annually, and it was still growing at over 20% annually when its population crossed 2 million.
Just imagine these numbers compounded. Even small variances can result in significantly different outcomes over time:
New York’s growth rate, however, declined less than Los Angeles or Chicago as the city grew larger. At around 3.5 million people, New York was still growing at over 3% per year, compared to less than 1% for LA and Chicago. This may not sound like much, but it's the difference between doubling in size every 23 years vs. every 70 years.
Now here's what I'm wondering after reading the article: Should we be thinking of city size as the single most important factor in determining urban growth? Because my mind immediately went to population densities, zoning controls, and other factors that might constrain or encourage growth.
But the data seems to suggest that, for many cities, this doesn't seem to matter over the long run. It is as simple as saying, "this city has X number of people and so it's more than likely growing at somewhere around Y% per year."
That said, what's up with China? What is it that allows a city of 2 million people to still grow at over 20%? Is it the sheer influx of people migrating from rural to urban areas? Or is it that you need a one-party authoritarian state to really clear the way for growth?
As cities get bigger there does appear to be a natural tendency toward slower growth. Part of this is the low base effect. But the declines are not always consistent and there are meaningful outliers. I am now curious to know what, for the most part, causes these differences.
As an add-on to yesterday's post about ground floor retail in mixed-use developments, I thought I would provide a few illustrative and real-world examples to demonstrate some of the challenges that I was trying to describe.
Note that this post is not meant to be critical of any specific projects; instead, it's intended to further explain some of the challenges facing developers, architects, policy makers, and everyone else involved in the built environment.
Let's start in Toronto. Below is an aerial photo of Ossington Avenue. For those of you who aren't familiar, this is one of the most desirable and coolest main streets in city. I mean, check out this recently completed office/retail building at 12 Ossington by Hullmark.
Earlier this year, Salt Lake City enacted new policy called the Downtown Heights and Street Activation Ordinance. As the name suggests, the ordinance addresses building heights, allows for taller buildings in the city, and works to improve ground floor animation. This is among other things.
We all recognize that blank walls (at street level) are suboptimal for urban vibrancy. But the thing about retail is that it doesn't work everywhere. Even if we really want it everywhere, that may not be possible, at least in the short-term. Retail is usually a lagging indicator. The demand typically needs to be already in place for it to do well.
That said, in really central areas, the correct decision could be to just mandate it everywhere. And that is what SLC has done in its central business district:
However, things get trickier in transitional or emerging areas where you're kind of just hoping that retail might someday work. From a development perspective, if we weren't convinced that the retail would work and if we were being forced to build it, we would underwrite it very conservatively. This might mean applying zero (or even negative) value to it. This way if we can't lease the space and it remains empty, at least it isn't fatal. But it does mean that the rest of the project needs to carry this loss.
Of course, now you still have a ground floor animation problem. You have empty storefronts. Though one argument might be that at least you've provisioned for a future where retail does eventually work. And if this does happen, then somebody was clairvoyant and you're happy that you built it. But if the area doesn't ever support good retail, well then you're stuck with an underperforming ground floor.
One alternative solution that can work on non-obvious retail streets is live/work. This way you build in some flexibility for the spaces to move toward retail (or other non-residential uses) if/when it becomes viable. But it's not a perfect solution. It's hard to make live/work suites entirely interchangeable. The ideal design parameters for retail are usually different than that of a home. Still, it can work reasonably well and provide needed flexibility.
It’s all very tricky. But at the end of the day, I think we can all agree that the objective is to limit blank and non-active faces on our principal urban streets. How we do that is the question. And sometimes it's more art than science.
However, when the above townhouse complex was built (circa 2005), Ossington was not the street that it is today. In fact, it used to be pretty scuzzy. When I moved to the US for grad school in 2006, I don't recall anyone going out on Ossington. Then when I returned in 2009, suddenly, everyone was going to restaurants and bars on Ossington.
So when this project was being planned, residential directly on the street, was probably the highest-and-best use, which is why that's what was built. But looking at it today, it feels like a suboptimal outcome for one of the most desirable retail streets in the city. And now that it has been built, it's unlikely to change anytime soon. Should retail have been mandated?
Here is another example from Toronto. This is the north side of High Park. In this case, the street (Bloor Street) is not a great retail street. It's single-sided because of the park. There's only a scattering of restaurants and small businesses. There are a lot of single-use buildings. And even some of the newish developments don't have any ground floor retail.
In this particular instance, it's certainly more of a stretch to force retail. But at the same time, I think there's an argument to be made that the edges of Toronto's primary urban park should do more. The buildings should be taller. The street walls should be more defined. And yes, maybe there should be more retail.
Now here's a counter example from Paris:
This is the 7th and there's absolutely no ground floor retail in sight and pretty much only blank and non-active facades. It's hard to imagine retail opening up here today or anytime in the future -- and that's okay. The streets are still narrow and walkable. And the buildings are just what you'd expect from the capital. The point here: ground floor retail can't and doesn't need to go everywhere.
Finally, let's return to Salt Lake City:
This is maybe the antithesis of our Paris example. 300 W is a wide street clearly designed for Toyota 4Runners. It's hard to imagine a lot of people walking around here. Even though it's relatively close to the central business district and it's on the edge of the emerging and very cool Granary District. (This is The Post District.) But you know what, retail seems to work just fine here:
You just need to think about it in the right way. SLC's wide streets and large blocks may not make for a broadly walkable environment. But they do give you the room to create your own internal street network and, of course, build a bunch of parking. And that's what was done and needed here.
I also find it interesting to think at this sub-block level and consider how it might become a new network and layer to the city over time. Maybe Salt Lake needs its own version of Barcelona's superblocks. And maybe this has already been considered.
So once again, ground floor retail is good. Everyone wants that cool coffee shop in the bottom of their building. But sometimes we miss the boat. Sometimes it's unclear what we should do. Sometimes it's not necessary or viable. And sometimes we get it just right. That's, I guess, retail.
However, when the above townhouse complex was built (circa 2005), Ossington was not the street that it is today. In fact, it used to be pretty scuzzy. When I moved to the US for grad school in 2006, I don't recall anyone going out on Ossington. Then when I returned in 2009, suddenly, everyone was going to restaurants and bars on Ossington.
So when this project was being planned, residential directly on the street, was probably the highest-and-best use, which is why that's what was built. But looking at it today, it feels like a suboptimal outcome for one of the most desirable retail streets in the city. And now that it has been built, it's unlikely to change anytime soon. Should retail have been mandated?
Here is another example from Toronto. This is the north side of High Park. In this case, the street (Bloor Street) is not a great retail street. It's single-sided because of the park. There's only a scattering of restaurants and small businesses. There are a lot of single-use buildings. And even some of the newish developments don't have any ground floor retail.
In this particular instance, it's certainly more of a stretch to force retail. But at the same time, I think there's an argument to be made that the edges of Toronto's primary urban park should do more. The buildings should be taller. The street walls should be more defined. And yes, maybe there should be more retail.
Now here's a counter example from Paris:
This is the 7th and there's absolutely no ground floor retail in sight and pretty much only blank and non-active facades. It's hard to imagine retail opening up here today or anytime in the future -- and that's okay. The streets are still narrow and walkable. And the buildings are just what you'd expect from the capital. The point here: ground floor retail can't and doesn't need to go everywhere.
Finally, let's return to Salt Lake City:
This is maybe the antithesis of our Paris example. 300 W is a wide street clearly designed for Toyota 4Runners. It's hard to imagine a lot of people walking around here. Even though it's relatively close to the central business district and it's on the edge of the emerging and very cool Granary District. (This is The Post District.) But you know what, retail seems to work just fine here:
You just need to think about it in the right way. SLC's wide streets and large blocks may not make for a broadly walkable environment. But they do give you the room to create your own internal street network and, of course, build a bunch of parking. And that's what was done and needed here.
I also find it interesting to think at this sub-block level and consider how it might become a new network and layer to the city over time. Maybe Salt Lake needs its own version of Barcelona's superblocks. And maybe this has already been considered.
So once again, ground floor retail is good. Everyone wants that cool coffee shop in the bottom of their building. But sometimes we miss the boat. Sometimes it's unclear what we should do. Sometimes it's not necessary or viable. And sometimes we get it just right. That's, I guess, retail.
