Americans travel something like 3 Trillion miles a year. If just 1% of cars are self driving thats 30 billion miles of testing a year. Far more driving than anyone could ever comprehend doing in a lifetime or 1000 lifetimes. Of course there will be some accidents during this time but the automation will quickly pass the abilities of 95-99% of the drivers out there fairly quickly.
As soon as this technology becomes available and is proven (100 million miles or so of driving) people will be running to get self driving cars. 1 hour commute becomes 1 hour of internet surfing or even sleep. At a certain point that 1 hour commute might become 30 minutes as the percentage of self driving cars goes up due to less accidents, less congestion, no rubbernecking, no sun glare issues, etc. I only have a 25 minute commute and would love a self driving car. You have a son or daughter turn 16 (15,17,18) are you going to let them drive themselves or use a proven self driving car. Would you prefer they go out with friends who just got their license or a program that has trillions of miles under its belt.
Self driving cars are a no brainer once the technology is in place. Of course there will be holdouts, there are people who still dont have cell phones, but the advantages far far far outweigh the risks.