This Space for Rent


There's an article in Salon magazine about skybusses, aka Personal Rapid Transit, which is a old way of combining all the bad properties of automobiles with all the bad properties of mass transit. For the people who don't know what skybusses are, they're computer driven automobiles that run on an elevated track ; you have to get on them at a station, but you can program them to drive to the station you want to go to without stopping on the way. Sounds like a good idea, doesn't it? The advantage of an automobile without having to actually drive, so who wouldn't like it?

Just for myself (and I am a long-time mass transit bigot who does not drive), I can think of a few reasons not to like it:

  1. If I'm going to drive an automobile, why not drive a conventional one? Skybusses run on dedicated guideways, so you're limited to where the guideways go. A regular automobile, as the auto uber alles contingent never stops bleating about, has a much larger network of guideways and can even occasionally travel off-guideway.
  2. Since they're single-occupancy vehicles, they're going to run headon into the feature known as congestion. And, unfortunately, one of the selling points for skybusses is that they're elevated railroads, which means that to add capacity you need to add more elevated railroad track. People don't really like elevated railroads, so I don't think that would fly very far.
  3. What about rush hour? In the mornings, you're going to use a lot of vehicles to get people into town and out. With automobiles, there are parking lots; they're already bought and paid for. I guess you could build special parking lots ("yards" is another name for them) or you could hope for some sort of reverse commute, but you're still looking at storing or moving a lot of empty vehicles.
  4. The advertisements for skybusses claim that they'll cost US$10 million/mile. I don't believe them; a trolley line using conventional railroad technology only rarely costs as little as US$10 million/mile, and the other so-called futuristic transit scheme (monorails) has been seeing 6x cost overruns on what has been promoted as a US$25 million/mile scheme.
  5. People have an amazing tolerance for filth in their private automobiles. They do not have such tolerance for filth in vehicles they hire from other people. Cleaning busses and trams is expensive and slow; I find it hard to believe that it's any cheaper and faster to clean 30x as many skybusses.
  6. The advertisements show spindly viaducts with the little tiny cars running on them. In reality, the viaducts aren't quite as frail as advertised. It's not a complete showstopper (highway viaducts and bridges are much more offensive), but people don't like elevated railways.

I'm not a transportation engineer. Some transportation engineers aren't impressed with skybusses either, but even if you ignore them the claims by the promoters are so extravagant that they set off my bogosity meter. And it doesn't help that the Salon article is sponsored by an automobile manufacturer.