Elon Musk recently posted this Twitter survey asking if we, the people, would like "super safe, Earthquake-proof tunnels under [our] cities to solve traffic." It was leading in that the "no" response was, "No, I like traffic." And it was initially vague in that it wasn't clear how these tunnels would be used. Though, most of us could probably guess. Elon later added in the thread that these road tunnels would be for zero emission vehicles only and they would be limited to EVs (from all auto companies, not just Tesla). Finally, Elon stated that these tunnels are not intended to replace other solutions, such as light rail, rather to supplement them.

At the time of writing this post, nearly 1.5 million people had responded to the survey and about 67% of them said "definitely" to Earthquake-proof tunnels. Elon's reaction: "Stop whining, subway Stalinists, the people have spoken." Notwithstanding the majority, this is a divisive topic and the reactions are mixed. City planner Brent Toderian responded by saying that this "solution" would merely result in more cars, more driving, and more emissions. Steve Jurvetson, on the other hand, argued that this would be the cheapest way to add lanes and prepare for the inevitable EV-only future. (Steve sits on Tesla's board and recently launched a venture fund that, among other things, invests in sustainable mobility.)

The crux of this divide is a view about how cities should work. And it often becomes like dogma. Is it optimal for us to all be driving around in individual vehicles -- EV or not? Will autonomous vehicles actually help solve the traffic problem? Or is building on the backbone of mass transit the only way to properly design a big and efficient city? Whether it's lip service or not, Elon seems to acknowledge that both cars and transit are important, and that both can work together to supplement each other.

What is clear to me is that cities, at the scale of say Tokyo, wouldn't function nearly as efficiently if it weren't for their extensive fixed rail networks. At the same time, there are many cities (or portions of cities) that do not have the prerequisite population and employment densities to support this same level of transit investment. And that has created a strong pull away from transit (and active transport such as cycling) toward private vehicles. Sprawling cities signal to people that they should probably be driving. This is one of the reasons why land use should never be separated from mobility discussions.

How autonomous vehicles change all of this remains to be seen. Though I do think it will make cars less private and more public transit-like. Studies show that most of us are pretty good at coming up with incremental improvements to the things we already know and understand. i.e. This is how I would make this car better. But we're far worse at coming up with and predicting tectonic shifts in the landscape. And autonomy is probably one of those shifts. But as long as our built form remains heterogeneous, I am inclined to believe that a mixture of mobility solutions will be needed. Maybe that means car tunnels. Or maybe it doesn't.

Photo by Ricardo Gomez Angel on Unsplash