I agree it's not a given. It's not unlike building new roads which sometimes can increase traffic. You can get people who haven't been able or willing to comm

I agree it's not a given. It's not unlike building new roads which sometimes can increase traffic. You can get people who haven't been able or willing to commute so far join the commuters. If self-driving cars are shared they might be driving more miles and be more likely to break down and block traffic. There is a possibility to optimize transport better using self driving cars but we may not actually take advantage of it. Even things like sharing self driving cars may not work in areas with larger sprawl because the probability of two people looking for the "same" ride within a certain time window and geographical area is small. In the city it's more likely but there are already solutions such as bicycles and public transport that work fairly well in dense areas. It is very difficult to predict the impact. Perhaps impossible.