If you're a regular reader of Architect This City, you'll know that I'm a big supporter of public transit. And that's because, as far as I can tell, it's the most efficient way of moving lots of people around a big city.

But more and more I've been thinking about how technology might change, or even disrupt, this school of thought. Which is why when I wrote this post a few days ago, I was careful to say that private cars aren't the mobility answer. Because in reality, cars likely aren't going to go away. We're just going to use them differently.

Here are the two things I'm thinking about most:

1. Driverless cars

I've written about driverless cars before in terms of how they might be used as a form of public transit. But I think it's worth revisiting them for a moment. There are lots of driverless car critics out there and they usually fixate on the fact that a car is still a car, whether or not you happen to be driving it. It still takes up the same amount of space in our cities. Or does it?

The key thing to keep in mind is that when we're not longer driving the vehicle, it opens up lots of different possibilities in terms of how they might be used and also how they might be designed. I was watching this fireside chat with the founders of Google the other night and, for them, driverless cars offer the possibility of solving two big problems: traffic and parking.

We know that parking takes up a lot space in our cities. But that's really symptomatic of the fact that the utilization rate for most people's cars is incredibly low. Most of the time a car is sitting parked and idle. But with driverless cars, they'll be able to drop you off at your destination and then continue on to pick up their next ride—thereby minimizing the need for all that parking.

This would bring the utilization rate way up for each car, which would also minimize the number of absolute cars that we'd need to have in our cities to move everybody around. Of course, this would mean that we'd be sharing cars. People wouldn't own cars; they would be an on-demand service.

2. Networked vehicles

This brings us to my second point: driverless cars will be networked cars. Again, I've written about this before, but I specifically wanted to raise it again because of a new service that Lyft just launched in San Francisco called Lyft Line.

The way it works is simple. You input where you're going and Lyft will match you up with others who are going to more or less the same destination. The routes get shared and this brings down the costs to everyday use. It runs on the same principles as the on-demand minibuses I wrote about in Helsinki.

But if you combine this with driverless cars, you're starting to get at something incredibly interesting. Now all of sudden you're getting the door-to-door convenience of private cars with many of the efficiencies of public transit.

So in my mind, it's very possible that platforms like Uber, Hailo, and Lyft could became major infrastructure backbones in a world of driverless cars. And if you think about it in this context, then I don't think the valuations for these companies should seem all that surprising. These are potentially huge innovations.

In the end, I don't know how this will all shake out. I don't think anybody does. I believe that strong public infrastructure (such as subways, light rail, and so on) will still be needed in big cities, but I'm starting to think that mobile apps and driverless cars will also form a big part of how we get around. Probably more so than most people think today.

Image: Flickr