About a week ago I wrote a post questioning what driverless cars will mean for cities. I ended by saying that that it feels as if we're going to see increasing tension between private and public transport.

What I meant by that was simply that conventional notions around private car use are going to change. And ultimately that is going to mean that we need to rethink public transport and how that fits into a broader urban mobility framework.

What do I mean by this?

The International Transport Forum at the OECD recently published a fascinating report called, Urban Mobility System Upgrade: How shared self-driving cars could change city traffic. And it deals with exactly the sorts of things I am thinking about.

The study looked of what might happen if all cars become self-driving in a mid-sized European city (specifically Lisbon, Portugal). They leveraged existing transportation data from the city, but replaced 100% of the human powered cars with two types of self-driving cars: TaxiBots and AutoVots.

TaxiBots were driverless cars that would be shared with multiple people at the same time. In other words, they were a kind of pseudo-public transit. And AutoVots we're your more conventional private taxi. They picked up one person at a time.

So, what did they find?

In the first scenario, they combined their TaxiBots and AutoVots with public transit (light rail) and discovered that the same number of people could be moved around with only 10% of the cars currently on the road. That's a 90% reduction!

They also found that the city needed 20% less on-street parking and 80% less off-street parking since driverless cars don't need to sit idle waiting for a driver.

In the second scenario, they removed mass transit from the equation. And in this instance they found that the city was still able to get around, but with an 80% reduction in the number of cars on the road. Remarkably, it also led to a 10% reduction in rush hour commute times.

These are pretty profound changes. Reducing the number of cars on the road by 80-90% is a significant change. 

But it's also why I've been thinking about the tension between private and public transport. As we get better at optimizing "cars" (their definition will change), what becomes the role of true public transit?

Ultimately, I think what will happen is a blurring of the two. In the example above, the TaxiBots served basically as small scale public transit. But that does not necessarily mean that true mass transit will become irrelevant. We're just going to need to rethink how the entire mobility network fits together.

I'd now like to bring this discussion back to Toronto for a minute.

As many of you probably know from this blog, Toronto is on the cusp of deciding what to do with the eastern portion of the Gardiner Expressway (an elevated highway that runs across the downtown waterfront). It will go to City Council next month. 

I firmly believe that we should remove it, but there many people who believe we shouldn't. The main objection seems to be that the traffic projections indicate that removing it could make commuting into downtown – by car – 3 to 5 minutes longer by 2031. 

By today's standards, I believe this concern represents an outdated way of thinking about cities and urban mobility. Adding more lanes is like loosening your belt to deal with obesity. However, it gets even worse when you think about urban mobility in the context of this post.

Given the profound transportation changes that are currently underway, I think there's a strong likelihood that the Gardiner projections we have today will be completely wrong by 2031. I don't know know for sure, but I'm guessing the models don't account for the efficiencies being created by driverless cars and peer-to-peer networks.

In other words, I am suggesting that those 3 to 5 minutes could prove to be a red herring. The relevant question should be: Which decision will allow Toronto to build the absolute best waterfront in the world? And in my opinion that leads to removing the Gardiner East.

If you feel similarly, I would encourage you to write your local City Councillor.