I agree with Bill... I don't see us switching to driverless cars in any sort of across-the-board way. Too many technical problems, hundreds of millions of "regular" cars on the road (would they be made illegal?)...too may issues, period. What about the auto insurance industry? They're not going to give up their billions of profit without a fight... but if the cars are driverless, who is at fault in a crash? Why would we need insurance at all (aside from maybe insuring the car itself for damage or loss), if nobody is driving the car?
Maybe one day we'll see "drone" cars here and there... maybe as taxis or small urban delivery vehicles, for example. Maybe even as large over-the-road haulers to replace the traditional semi... but I just can't see us all in driverless cars (and trucks) any time in our lifetimes.