One thing people don't seem to get in this thread, is I'm pretty sure most self driving cars will be FLEETS, which means individuals won't own them anywhere close to the ownership rates of traditional cars. You will only have access to a car when you need it. To make it even more interesting, through AI, your riding habits will be taken into account and therefore you won't even need to call an uber or self driving car to pick you up, it'll already be waiting for you outside. An easy example is through AI, it will know your shopping and work habits, and be ready to pick you up and you won't need to call the car to come get you. This frees up the cars to go where they are needed, rather than sitting in your driveway.
This points to less cars on the road in my opinion.
Therefore, it WILL NOT be more expensive.
Paying per mile or however it will be will still be cheaper than the majority of Americans who have monthly car notes, maintenance costs, insurance costs, accessories, upgrades, and what about traffic tickets and violations? Those will be a thing of the past!
I believe in the long run it'll be cheaper, safer and more efficient.
And for the uninformed ppl who say there are "numerous accidents" and "the technology isn't here yet," look again because you haven't. Uber is testing in Pittsburg right now, Tesla, Google, etc....testing is going on for years, so in 15yrs or so, it'll start becoming mainstream.
I'm sure there will be people driving their own cars still, but those ppl will pay more for their own insurance, car notes, maintenance, etc.
Embrace technology instead of telling everyone to "Get off my lawn!"