That will work well when one or two people in most of those houses are commuting, dropping kids at school, and/or running errands at about the same time. /s I fully expect that autonomous vehicles at some point will marginally expand the ranks of people who are marginal car owners and will just effectively taxi. But if you have daily use that Uber/taxis doesn't solve, regularly use a personal car to drive places, have your vehicle configured for things like care seats for kids, etc. you'll do without full autonomy in favor of presumably improved automation in your personal vehicle.

> That will work well when one or two people in most of those houses are commuting, dropping kids at school, and/or running errands at about the same time. /s

I don't really understand what you're arguing here.

At most, doing that with self-driving cars would require the same number of cars that already exist. Right?

That's good enough for me to put it in the "practical" category. What's your standard for "practical"?

But more realistically, even at peak use there's a lot of cars sitting there not moving. Make some do taxi work and you can cut numbers significantly.

> I fully expect that autonomous vehicles at some point will marginally expand the ranks of people who are marginal car owners and will just effectively taxi.

Not just them, it can displace a lot of second and third cars even when it's barely touching primary cars.

You said: "In a typical suburb, providing a 2-3 minute wait would require one idling self-driving car per hundreds of houses." with the implication that this is an alternative to car ownership and would vastly reduce the number of cars.

>it can displace a lot of second and third cars even when it's barely touching primary cars.

I agree although things like Uber and Zipcar have already reduced the need for lightly-used second cars which are what I mean by marginal cars.

All I'm saying is that if the only way to get fully autonomous vehicles is through a third party service, most people will pass and just take whatever autonomous features they can get in a vehicle they buy/lease and live with that. I certainly would.

Very few people would argue that having the option of owning a vehicle capable of safe fully autonomous operation (with manual override) is a bad thing. We're just saying that having full autonomy only available as a third-party taxi service just isn't very interesting relative to today except perhaps at the margins.

> with the implication that this is an alternative to car ownership and would vastly reduce the number of cars

The point I was trying to make is that you need very few idle cars on top of the ones in active use. A fraction of what suburbs already have.

It could be a vast reduction in the number of extra cars over the peak concurrent number.

> I agree although things like Uber and Zipcar have already reduced the need for lightly-used second cars which are what I mean by marginal cars.

Somewhat, but self-driving cars are more effective in multiple ways. They don't need to be nearly as cost-effective while idling, and they can come to your doorstep instead of making you walk to them. There's nothing like a zipcar near me.

> Very few people would argue that having the option of owning a vehicle capable of safe fully autonomous operation (with manual override) is a bad thing. We're just saying that having full autonomy only available as a third-party taxi service just isn't very interesting relative to today except perhaps at the margins.

I think it goes well beyond the margins if the price works out. Or maybe your definition of "margins" is a lot bigger than mine in which case we agree and even a change at the margins is a big deal.

But also, even if the average person wouldn't switch, that's different from it being utterly impractical to switch.