I think that in the US, it will largely be a matter of "You'll take my car when you pry the steering wheel from my cold, dead fingers." But I have the feeling that the time isn't distant when the smoggiest cities will bar their streets to car traffic: and that, inside the city, people will be required to use public transit, walk or bike. Or possibly at least scooters or electric carts.

At the moment it isn't a serious consideration, because nobody has done it yet. But as soon as one city gives it a successful try, I bet we will see many more considering it.