Anytime you make something cheaper, easier to use, more useful and/or more efficient you get an increase in usage. Autonomous electric cars are all 4, and will lead to a dramatic increase in the number of miles driven. Some of those miles we can imagine (for instance sending your car on a dead-head journey somewhere for somebody else to use it), but most of the increase will probably be from new usage models that we don't expect.
There may be a decrease in the number of cars; the increase in car sharing may be higher than the increase in miles, but I doubt it.
But congestion? That's going to get a lot worse, it's not going to be the utopia that people here seem to expect.
There may be a decrease in the number of cars; the increase in car sharing may be higher than the increase in miles, but I doubt it.
But congestion? That's going to get a lot worse, it's not going to be the utopia that people here seem to expect.