Chris Anderson: Elon, hey, welcome back to TED. It’s great to have you here.
Elon Musk: Thanks for having me.
Chris Anderson: So, in the next half hour or so, we’re going to spend some time exploring your vision for what an exciting future might look like, which I guess makes the first question a little ironic: Why are you boring?
Elon Musk: Yeah I ask myself that frequently. We’re trying to dig a hole under LA, and this is to create the beginning of what will hopefully be a 3D network of tunnels to alleviate congestion. So right now, one of the most soul-destroying things is traffic. It affects people in every part of the world. It takes away so much of your life. It’s horrible. It’s particularly horrible in LA.
Chris Anderson: I think you’ve brought with you the first visualization that’s been shown of this. Can I show this?
Elon Musk: Yeah, absolutely So this is the first time — Just to show what we’re talking about. So a couple of key things that are important in having a 3D tunnel network. First of all, you have to be able to integrate the entrance and exit of the tunnel seamlessly into the fabric of the city. So by having an elevator, sort of a car skate, that’s on an elevator, you can integrate the entrance and exits to the tunnel network just by using two parking spaces. And then the car gets on a skate. There’s no speed limit here, so we’re designing this to be able to operate at 200 kilometers an hour.
Chris Anderson: How much?
Elon Musk: 200 kilometers an hour, or about 130 miles per hour. So you should be able to get from, say, Westwood to LAX in six minutes — five, six minutes.
Chris Anderson: So possibly, initially done, it’s like on a sort of toll road-type basis.
Elon Musk: Yeah.
Chris Anderson: Which, I guess, alleviates some traffic from the surface streets as well.
Elon Musk: So, I don’t know if people noticed it in the video, but there’s no real limit to how many levels of tunnel you can have. You can go much further deep than you can go up. The deepest mines are much deeper than the tallest buildings are tall, so you can alleviate any arbitrary level of urban congestion with a 3D tunnel network. This is a very important point.
So a key rebuttal to the tunnels is that if you add one layer of tunnels, then that will simply alleviate congestion, it will get used up, and then you’ll be back where you started, back with congestion. But you can go to any arbitrary number of tunnels, any number of levels.
Chris Anderson: But people — seen traditionally, it’s incredibly expensive to dig, and that would block this idea.
Elon Musk: Yeah. Well, they’re right. To give you an example, the LA subway extension, which is — I think it’s a two-and-a-half mile extension that was just completed for two billion dollars. So it’s roughly a billion dollars a mile to do the subway extension in LA. And this is not the highest utility subway in the world. So yeah, it’s quite difficult to dig tunnels normally. I think we need to have at least a tenfold improvement in the cost per mile of tunneling.
Chris Anderson: And how could you achieve that?
Elon Musk: Actually, if you just do two things, you can get to approximately an order of magnitude improvement, and I think you can go beyond that. So the first thing to do is to cut the tunnel diameter by a factor of two or more. So a single road lane tunnel according to regulations has to be 26 feet, maybe 28 feet in diameter to allow for crashes and emergency vehicles and sufficient ventilation for combustion engine cars. But if you shrink that diameter to what we’re attempting, which is 12 feet, which is plenty to get an electric skate through, you drop the diameter by a factor of two and the cross-sectional area by a factor of four, and the tunneling cost scales with the cross-sectional area. So that’s roughly a half-order of magnitude improvement right there.
Then tunneling machines currently tunnel for half the time, then they stop, and then the rest of the time is putting in reinforcements for the tunnel wall. So if you design the machine instead to do continuous tunneling and reinforcing, that will give you a factor of two improvement. Combine that and that’s a factor of eight. Also these machines are far from being at their power or thermal limits, so you can jack up the power to the machine substantially. I think you can get at least a factor of two, maybe a factor of four or five improvement on top of that.
So I think there’s a fairly straightforward series of steps to get somewhere in excess of an order of magnitude improvement in the cost per mile, and our target actually is — we’ve got a pet snail called Gary, this is from Gary the snail from “South Park,” I mean, sorry, “SpongeBob SquarePants”. So Gary is capable of — currently he’s capable of going 14 times faster than a tunnel-boring machine.
Chris Anderson: You want to beat Gary.
Elon Musk: We want to beat Gary. He’s not a patient little fellow, and that will be victory. Victory is beating the snail.