In the world of fully autonomous vehicles, they would inevitably opt to save that $10 per day and have their car drive them to work, drop them off, take itself home, only to return when the driver summons it at the end of the day. That makes a 20km day a 40km day. And imagine that for the millions of households across the city.
Second, congestion. AVs will ensure that time in the car is more pleasurable and useful. Being stuck in a traffic jam might not be such a pain if you could be working, reading, watching a movie, having a coffee with friends, playing with the dog, or starting Friday night drinks early.