Views / Opinion

Math myth-busting some of our worst urban planning misconceptions

To be blunt, the math suggests that we’ve been doing a lot of things wrong.

A study in Copenhagen (where the full cost of transportation choices are routinely calculated) found that when you factor in costs like time, accidents, pollution and climate change, each kilometre cycled actually gains society 18 cents!

Torstar news service

A study in Copenhagen (where the full cost of transportation choices are routinely calculated) found that when you factor in costs like time, accidents, pollution and climate change, each kilometre cycled actually gains society 18 cents!

First, an admission: when I was in school, math was my least favourite subject.

But these days, as someone who advises cities and best-practice developers around the world on what I call "advanced urbanism," math just might be my favourite thing to talk about.

That's because when it comes to designing and building smarter and more successful places, we understand more about the quantifiable science of cities — the "math of city-making" if you will — than ever before.

When it comes to great cities, I'm the first to point out that not all that counts can be counted, but most of the things we can count lend support to smarter ways of thinking about how our cities grow and change. To be blunt, the math suggests that we've been doing a lot of things wrong. And the same math can help us understand how to do it better.

The City of Toronto is spending billions to rebuild a portion of the Gardiner elevated expressway that serves fewer than 5,000 drivers during peak hours.

Torstar News Service

The City of Toronto is spending billions to rebuild a portion of the Gardiner elevated expressway that serves fewer than 5,000 drivers during peak hours.

Here are just a few examples:

  • A common political argument is that bike and transit riders should "pay their own way." A study in Vancouver however suggested that for every dollar we individually spend on walking, society pays just 1 cent. For biking, it's eight cents, and for bus-riding, $1.50. But for every personal dollar spent driving, society pays a whopping $9.20! Such math makes clear where the big subsidies are, without even starting to count the broader environmental, economic, spatial and quality-of-life consequences of our movement choices. The less people need to drive in our cities, the less we all pay, in more ways than one.
  • Another study in Copenhagen (where the full cost of transportation choices are routinely calculated) found that when you factor in costs like time, accidents, pollution and climate change, each kilometre cycled actually gains society 18 cents!
  • A recent American study suggested that compact development, on average, costs 38 per cent less in up-front infrastructure and 10 per cent less in ongoing service delivery than conventional suburban development, while generating 10 times more per acre in tax revenue. Many cities overbuilding the suburbs are putting their fiscal future at risk — and that’s before the bigger picture costs are even included.
  • Over the last decade, Canadian cities like Calgary, Edmonton, London, Halifax, Regina and Abbotsford have been doing the hard math on the real costs of how and where they grow — not just up or out, but how smarter design choices save costs. The resulting math has been powerful — tens of billions of dollars more of public cost for car-dependant suburban growth than for smart infill — and I haven't even yet seen such a study that includes all the full and life-cycle costs of our growth choices. Once these shocking numbers are revealed, municipal leaders can't "un-know" them, no matter what political ideology they live by.

Want more examples? There's math showing that replacing on-street parking with safe, separated bike-lanes is good for street-fronting businesses. That crime goes down as density goes up. That providing housing for the homeless actually saves public money. That you can move more people on a street when car lanes are replaced by well-designed space for walking, biking and transit.

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Many of the biggest fear-based myths that get raised in city-building conversation are shown to be untrue when you apply cold, hard counting to the conversation. And that's before we even get to the many intangible and un-countable — but equally well-demonstrated — benefits of smarter city-making.

Vancouver's cycling traffic has spiked dramatically since the city embarked on a plan to greatly increase the city's bicycle infrastructure.

Metro/File

Vancouver's cycling traffic has spiked dramatically since the city embarked on a plan to greatly increase the city's bicycle infrastructure.

It's important to remember that if we just throw a lot of numbers around, people can easily fall asleep! I sure would.

But when you combine this unprecedented understanding of the math of cities, with a much more engaging, personal and persuasive approach to story-telling, then the conversation can get much more interesting and successful.

So that's why I now love math. If we're not boring about it, it can add up to much better cities.

Brent Toderian, MCIP, is a leading national & international city planner and urbanist with TODERIAN UrbanWORKS; Vancouver BC's former chief planner; & the President of the Council For Canadian Urbanism. Follow him on Twitter @BrentToderian.