Brandon Donnelly — Daily insights for city builders. Published since 2013 by Toronto-based real estate developer Brandon Donnelly. — Page 342

Many of you probably didn't click through on this link in yesterday's post , but it was a link to a book called Emergent Tokyo -- Designing the Spontaneous City . What this book is largely about is the idea that Tokyo -- usually considered to be the largest urban region in the world -- is more the result of bottom-up actions than top-down actions. In other words, it is a kind of complex and self-organizing system.

Some of you may be reading this and thinking that the result would be chaos. But the opposite is, in fact, true. Despite being the largest urban agglomeration in the world, Tokyo is consistently viewed as one of the most livable big cities in the world. How is that possible?

One topic that we've been talking about on this blog recently is the planning approach of mandating ground-floor retail in new developments. While certainly good intentioned, this is one example of top-down planning. We are saying, "retail needs to go here because."

The problem, as we have talked about, is that the market may not want it. It may not actually be viable or desirable. Of course, it is a delicate situation. Because if you don't provision for it, then you might block it from ever being possible on sites where it clearly makes sense. (We spoke specifically about this, here .)

There is also the opposite question of: where are we not allowing retail?

Maybe there are places where retail activity would be viable today, except it's currently not permitted. One concrete example of this is Toronto's laneways. Right now, we only allow residential (throughout our "Neighbourhoods"). But there many people, including myself and planner Blair Scorgie , who have been arguing that they should be mixed-use:

Would office and retail uses actually work in Toronto's residential laneways? I frankly don't know. Because they're not allowed today, it's largely impossible to know. If we allowed these uses and nothing happened, then we'd have a better idea that there's little demand for it. (I say a better idea because there still could be other obstacles in the way.)

On the other hand if we decided to mandate non-residential uses in our laneways and nobody did anything, two things might then happen. One, we'd be similarly led to believe that there's little to no demand. And two, we'd probably be sacrificing the residential use, for which we can say today there is clear demand.

There are also the considerations that demand will almost certainly change over time and be inconsistent across different locations. For instance, maybe retail doesn't work in this laneway, but it will work in that laneway. Can we actually plan for this?

Top-down approaches generally assume that we know all or many of the answers. It presumes that we know that this street should have ground-floor retail and this street should not. It's also about control. More bottom-up approaches admit that it's impossible to plan for everything and that there could be latent potential that we're not even thinking about.

Of course, there is something naturally unsettling about this approach because it is, by definition, unknowable. And it relinquishes a certain amount of control. Maybe a restaurant will appear here or maybe it won't. Maybe someone will open a small office in this laneway or maybe they won't. Either way, the potential for change exists.

But I think this should be seen as empowering, transparent, and highly efficient. It is a way of reducing the barriers to entry and allowing more urban creativity and ambition to shrine through. I believe, for example, that if we made it easier, cheaper, and possible to open a small restaurant (perhaps in a laneway), we would have more and overall better restaurants in the city.

And as we have seen in the case of Tokyo, the result of more flexibility is not necessarily chaos. It can be a highly livable city that has people wondering, "how did they manage to plan such a large city so well?"

Photo by  Kentaro Toma  on  Unsplash

I know I know this, but this is still an alarming chart:

This is saying that, as of 2016, over 36% of Americans were considered to be obese. In Canada, the number was just under 30%. And in the UK, it was just under 28%, which is the highest rate in Europe.

We often talk about the health benefits of living in a walkable community. And there's lots of research to back up that this is in fact the case: obesity rates tend to be inversely correlated with higher prevalences of active transportation (walking, cycling, and so on).

But we also can't ignore diet. And here's what has happened in the UK , as well as in other Western countries:

An increased reliance on cheap, ultra-processed food, which accounts for 57 per cent of what Britons eat according to a 2019 study conducted by researchers at the University of São Paulo, suggests that the health crisis is unlikely to change anytime soon without intervention, argue campaigners.

It can be hard to eat healthy, especially if you don't have a lot of money and you live a busy life. But in my view, we need to change the course of this graph. And two very good places to start looking would be (1) our built environment and (2) the Japanese diet .

Actually, now that I think of it, Japanese cities would be a good place to look as well.

Chart: FT

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  Shenzhen , 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.