I tweeted this out last week:

Not surprisingly, the responses were divided. Some responded saying that beauty is more important than density, and a lot of people were quick to point out that there's good density and there's bad density. And because I can appreciate both of these comments, it made me think that I should probably elaborate on my glib tweet.

The points I was trying to vaguely imply are the following.

More often than not (at least for North American cities), I think our problem is not too much density, it's too little. This translates into cities that aren't walkable, aren't conducive to transit, and that are overall less sustainable. Right now, every mayoral candidate in Toronto is promising to fix our crippling traffic congestion. I don't know how they're going to do it, but they're promising it because they know it's something people are pissed off about.

But here's my take: counterintuitively, the problem is not enough density. The problem is that too many people in our region have no reasonable way to get around without a car. So they're forced to drive. The way you fix this not as simple as more traffic enforcement or better signal timing. Good luck! You fix it through density, because density is what makes other forms of mobility suddenly possible.

All of this is not to say that density alone will render you a great city. Obviously things like beauty also matter a great deal. But in my opinion, density is a fundamental component. Because what good is beauty if you don't have any urban vibrancy? The answer is that you probably don't have a real city.

The other point I was trying to make is that space and density are both relative and oftentimes difficult to understand. We think building height and density are correlated, but that's not always the case. Look at Paris or Barcelona. We also like to make a lot of spatial rules that we think are right and make our cities better: streets should be at least this wide, buildings should be no taller than the width of the street, and so on.

But here (pictured above) is a street that narrows to around 6 meters and has buildings that are probably 2.5-3x the width of the right-of-way. Sure, it also happens to be beautiful, historic, and Italian. But what would happen if you maintained this same beauty and made the street 5x as wide and lined up parking in front of the stores?

Somehow it wouldn't be as enjoyable as what you see here.

Building height and density are not one and the same. You can have tall buildings configured in a low-density way (think post-war towers in the park). And you can have low/mid-rise buildings configured in a high-density way (think Paris and Barcelona). This is one of the reasons why it is important to decouple density and tallness when thinking about our cities.

This line of thinking is the approach that a recent study took when trying to determine the optimal built form for minimizing climate impact. In the study they define four building typologies: 1) high density, high-rise, 2) low density, high-rise, 3) high density, low-rise, and 4) low density, low-rise.

What they found was that taller environments tend to have higher life cycle GHG emissions, but that lower-density environments are (obviously) far more land consumptive. To determine life cycle GHG emissions they looked at both embodied and operating emissions, which is why the taller stuff didn't score as well under their methodology. There's typically a lot of concrete and steel in tall buildings.

This lead the team to conclude that if you want to optimize around climate impact, you should probably aim for that perfect middle ground: dense, but not super tall.

But as Joe Cortright (City Observatory) rightly pointed out in his email newsletter, one of the big limitations of this analysis is that it does not consider transportation-related impacts. And since we know that transportation is one of if not the largest source of GHG emissions and that how we get around is heavily dependent on land use patterns, it is probably an important piece to consider.

Photo by Alfons Taekema on Unsplash

I was just reading about London's plans to pedestrianize Oxford Circus with two new semi-circular pedestrian piazzas (pictured above). And it reminded of two things.

One, there are silver linings to this pandemic. And one of them is that it has forced us to rethink how we allocate public space and how we engage with it. It is incredible seeing Toronto right now with so many outdoor patios in full swing. Why eat inside when you can eat outside? We should have been doing this all along.

Two, the transformation of Toronto's Yonge Street cannot happen fast enough. We are sorely missing a pedestrianized spine through the middle of our downtown. This portion of Yonge Street currently looks like shit and I know that we can do much better.

Think La Rambla in Barcelona. Grafton Street in Dublin. Lincoln Road in Miami Beach. These are the streets that seem to always draw you in. They are places where public life can play out. I'm pretty sure that I have never once visited any of these cities and not walked these streets.

Thankfully Yonge Street's transformation is underway. So let's make it truly remarkable and one of the most beautiful streets in the world. That should be the bar we set for ourselves.

Image: Westminster City Council