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> - public transit disappears? though driverless buses would be cheaper too. Driverless cars would be a very poor replacement for public transit in traditional

> - public transit disappears? though driverless buses would be cheaper too. Driverless cars would be a very poor replacement for public transit in traditional cities. Transit has far, far, higher density than cars do, no matter who's driving them. The problem with cars, for the most part is the immense amount of space that is dedicated to support them, usually at the expense of all other uses, and of the people living there. Driverless cars would reduce this somewhat, but as a 1-for-1 replacement, not nearly enough to be useful. Probably the best effect of driverless cars will be the other effects you mention: taxi-type services will get cheaper, thus fewer people will own cars, thus fewer people will feel tempted to drive everywhere, thus other modes will get more use, and cities will become more pleasant as car infrastructure shrinks, thus causing even fewer people to drive, etc, etc. [and yeah, driverless buses etc, are a great application of the tech, maybe more so than actual cars as they're more amenable to simplifications (dedicated routes with supporting infrastructure, etc)...]

Zigurd 13y ago
I think that's an open question. City busses are only about at parity with cars for fuel economy, due to mostly running at low load factors. That's not a perfect proxy for space, but load factor would be part of the space calculation, too. However I could see some kind of minibus that could run at both higher density and higher load factor, respond to demand, and sit idle when there is no demand being the optimal kind of vehicle.
- snogglethorpe 13y ago
  I suspect fuel efficiency based on load factors is a very bad proxy for space usage, as fuel efficiency will be calculated as an average, whereas infrastructure is (necessarily) dictated by peak usage. This is true for all modes, of course, but because mass-transit is much more efficient at the high load factors that occur during peaks, it ends up being much significantly more space efficient as well. [Especially in the U.S., automobile infrastructure is actually often excessive even for peak usage, due to things like ill-considered minimum parking regulations and local politics ("I widened roads! Vote for me!"). But that's a cultural/political problem, not a technical one.] Another factor in favor of mass transit is that it tends to result in much more focused development around transit networks, resulting in denser and more walkable communities. The fact that it "can't go everywhere" is actually a benefit when it comes to the urban form...

Zigurd 13y ago

I think that's an open question. City busses are only about at parity with cars for fuel economy, due to mostly running at low load factors. That's not a perfect proxy for space, but load factor would be part of the space calculation, too. However I could see some kind of minibus that could run at both higher density and higher load factor, respond to demand, and sit idle when there is no demand being the optimal kind of vehicle.

snogglethorpe 13y ago
I suspect fuel efficiency based on load factors is a very bad proxy for space usage, as fuel efficiency will be calculated as an average, whereas infrastructure is (necessarily) dictated by peak usage. This is true for all modes, of course, but because mass-transit is much more efficient at the high load factors that occur during peaks, it ends up being much significantly more space efficient as well. [Especially in the U.S., automobile infrastructure is actually often excessive even for peak usage, due to things like ill-considered minimum parking regulations and local politics ("I widened roads! Vote for me!"). But that's a cultural/political problem, not a technical one.] Another factor in favor of mass transit is that it tends to result in much more focused development around transit networks, resulting in denser and more walkable communities. The fact that it "can't go everywhere" is actually a benefit when it comes to the urban form...