I actually think it may reduce it. The options that self-driving cars open up are almost mind-boggling if you think about it. Especially if you combine it with a logistics/mass transit mindset. People no longer need garages or driveways, you greatly reduce the need for parking, and you could gain tremendous energy efficiency by units of transportation linking up…which would also allow for traveling of longer distances with fewer charging stops. Combine that with the fact that we’re on the precipice of flying cars…the world will look quite different in 30 years.There are many groups that cannot drive: children, disabled, elderly. For those, having a reliable self driving car opens doors previously closed (like handicap doors!) such as, grocery store runs, Dr appointments, and after school activities. Not to mention it would probably raise the average driver's DQ by removing less comfortable drivers from the wheel and overall make roads safer.
I'd be more concerned with urban sprawl as it opens up more options for commuting.