Tesla's full vision of self-driving cars that form a ridesharing network would indeed dramatically reduce the number of cars. Most cars sit around unused, taking up space. When idle time for cars drops, then demand for cars will drop.

This also means we'll have much less need for parking lots, etc. Parking infrastructure consumes a huge portion of prime urban land. Curbside parking alone is sometimes estimated at 10%.

Thus, it would also reduce sprawl, and thereby reduce both commute times and the amount of energy required to commute.

All of those things would be eco-friendly, if we can move in that direction. Particularly once we shut down all the coal plants.