Publicness is not the only benefit of public transportation. Trains and buses are incredibly efficient per passenger mile. They also take up a lot less space than cars, and last longer and cost less per passenger to manufacture. Making a car driverless doesn't solve these problems.
The public transportation the public uses beats the one they don't.
Not to mention that communal vehicles would make electric cars suitable for any length of trip— Forget about exchanging batteries, just swap cars at the charging station.
Which country? It's a global problem (and this is a global forum). Kudos to Nevada for having the presence and foresight to pass this legislation. It opens up a world of possibilities for future transport options, and whilst it will take a while for the public to catch up and accept both the technology, and the transport changes it enables, this is a huge step in the right direction.
I'm not blind to the existence of transportation issues in other countries, but insufficient (read "nonexistent") public transportation is often noted as a predominantly (while not uniquely) American problem. Certainly we represent the archetype of the "one car per person" catastrophe.
The emergence of communal, computer-controlled electric vehicles could turn that around completely, so I don't think it's too out of line to be talking primarily about America at this stage.
Spain for one. I know which Nevada the legislation was passed in, but your comment made the implicit assumption that everyone reading it is in the US.
"insufficient (read "nonexistent") public transportation is often noted as a predominantly (while not uniquely) American problem"
As is egocentrism.
Seriously, though. "This country", as in, the country where I live, which is coincidentally the same one under discussion. You can relax a little with the righteous indignation.
You'd still need roughly the same number of 'communal' cars during those peak times. Though people may be more likely to car-pool.
Even the trivial variation of most US 'flex time' starts wouldn't help much. The difference between 8 and 9 isn't great enough for very many cars to make it from a business park at 8 back out to pick up another passenger and then back to another employer before 9.
What might really help, is 'communal' cars augmenting the US's sparse transit system. e.g. The communal car takes you to the train/bus stop. A communal bus departs as soon as it can. The communal car takes you to your final destination.
That way the cars are doing shorter round-trips, serving more people (necessitating fewer cars) and people are more apt to use the public transport because they aren't worried about the current big problems of US transit: 1. parking at the transit stop 2. how to get from the transit destination to where they really want to go 3. what happens if you miss the train/bus time (the car can just complete the trip)
Of course there will be some limit to capacity, as with any public transportation. But having to wait a bit for a car isn't going to put off commuters who are used to spending hours a day waiting in traffic.
A few weeks ago, I left my house for the grocery 2 miles away. I followed a car from my subdivision to the grocery. After shopping, I followed the same car back from the grocery to my subdivision.
Urban sprawl is a gigantic problem that we need to address, and soon. It not only affects transportation - there's general maintenance cost, social effects, land use, etc.
How far would you be willing to commute right now? OK, what if you could sleep or play videogames en route?
But you can do the same on a train or bus already. I think part of why people don't use them as much is because of the inconvenience of working around their schedule, and first and last mile commutes (because the train doesn't go to your office). Networked, driverless cars could play a part in the larger public transport system to alleviate these two points of pain of commuters.
Especially in the west coast, American cities were built to be navigated by cars. Even today, the very fact that carpool lanes in most parts of California are designated for 2 people/car, not 3 implies we already have separate vehicles for each passenger. If we can take advantage of the road infrastructure and cut down on the need to own a car, it will be a huge benefit to lots of people. See how popular ZipCar is, precisely because of this sort of benefit.
A lot of the gridlock in my city comes from people doing stupid things that force other drivers to slow down to avoid a wreck. Automated cars would reduce the impact of bad drivers by removing them from the equation.
You'll have to be able to keep one of these public cars at your place overnight for it to work (unless it drives itself home empty!).
Anecdotes are not data, but our local buses (city of ~50k) rarely have more than one rider, and a plurality of those I see have zero riders. In our case, these autonomous cars would be a much more efficient solution.