Saturday, May 19, 2018


I thought the one good thing about the self-driving car craze is... at least we don't have to hear about stupid PRTs anymore. And then Elon comes along and says... let's build a PRT (personal rapid transit) system... underground!

It isn't even a new idea. If the dude can really improve tunneling technology to make it massively cheaper, good for him. I am not an expert but my understanding is that this really wasn't a problem that needed to be solved in that the expense of tunneling isn't really putting a machine into the ground and telling it to go. Anything's possible I guess. But the idea of a PRT subway isn't new. It's been the fantasy of the "like a subway, but just for me" and "like a taxi, but cheap" and "if you ignore all the actual expenses, this isn't very expensive" and "if we promise the Jetsons, we can keep building highways until they arrive" crowds.

Aside from many other issues, the problem with these systems is that even their fantasy versions tend to ignore the fact that employment is concentrated in both time and space. Meaning, rush hour is a thing and even in Los Angeles employment centers are a thing, and if lots of people want to ride the underground taxi at 5pm there's no way your underground taxi system, even the fantasy version, can handle the capacity that a subway train can.

The Victoria Line in London can currently run 30 trains per hour. Not 30 train cars, 30 trains. 1000 people per train (theoretically more, but realistically).

When the DNC was in Philly in 2016, all the muckity mucks complained that it was too damn hard to get their Ubers when they all spilled out of the arena at precisely the same time. That's basically the problem (among others) of a PRT system. Just picture the taxi line at the airport. It really doesn't matter how many taxis you have waiting. You still have to load them, somehow. A couple of people at a time. They should've taken the subway.