I think you are on to something with an increase in vehicle miles. Travel will be much easier, in a sense "cheaper" and there will be more of it. So long as the vehicles are electric and charged with greenhouse free electricity, I'm not sure it much matters.

I do think there will be higher utilization of pool or fleet vehicles. You can get exactly the car you need for the trip, without the expense of owning. Kind of car timeshare. Just you going to work - request the single passenger economy car. Family of four going out to the movies? Get the economy for four vehicle. Vacation time? The family truckster has been reserved for two months and arrives at your driveway the night before for packing and a late night nap-time departure.

Hauling a bunch of crap? The F-150 shows up ready for loading and automatic departure.

The impact on mass transit will be interesting. People are the largest expense of Metro Transit, so mass transit will become a lot less expensive to operate.

Interesting times to come, so long assuming we don't cook the planet so quickly that none of this ever happens anyway.