the question is what kinds of cars can best utilize the lane capacity we have.

The kind that can take 50-100 passengers instead of 1-5?

It’s not about who’s driving the vehicle, it’s about what’s a sustainable ratio of people: vehicles.

Make self-driving vehicles, by all means. Autonomy won’t solve the fact that number of people in the city divided by 5 (best case scenario, but we all know it’s more like 2 or 1) equals vastly more cars than there’s road surface.

We have autonomous subways in Europe btw, they work very nicely and they minimize the distance between successive trains at rush hour. I’m all for driving automation but the circumstances need to make sense. Subway automation won’t make up for train capacity or station capacity, for example, once a train or platform fill up they fill up, end of story.