It's possible the incremental cost of a driverless car trip from a shared pool (like zipcar in that respect) would be higher than the cost of driving your own c

It's possible the incremental cost of a driverless car trip from a shared pool (like zipcar in that respect) would be higher than the cost of driving your own car, due to the fact that when you're not using your personal car it's just sitting around in your driveway collecting rust. That would be an incentive to reduce the number of trips.