Suspect your autonomous EV will be drivign at 50-60mph not 90 haha... the battery drain would be insane.I suspect a lot of the general public would adopt far faster if they can simply sit back in the outside lane of the motorway at 90mph whilst the car does the driving, rather than sitting in the other lanes at 70 max.
But as it's autonomous you could do stuff while driving so although it takes longer you might not care as much.