This could make traffic worse. The only thing keeping bad traffic from getting worse is that past a certain degree of badness, some people start choosing to can

This could make traffic worse. The only thing keeping bad traffic from getting worse is that past a certain degree of badness, some people start choosing to cancel or defer driving trips because they are not willing to drive with that degree of delay and/or annoyance. Making traffic easier to put up with, will have the same effect as reducing the price of any good would have -- increase the amount "consumed" Self driving cars will lead to worse traffic unless tolls go up enough to make up for it