Driverless cars are not going anywhere until they can prove themselves 20% superior than the average driver in ALL the following conditions:
Dealing with Rain (visibility and deep water on the road),
Hard to see tire eating potholes causing damage,
Ice and snow (on road and caking on instruments),
Snow accumulation ruts, causing car to move unexpectedly,
Evasive driving - cutting across a lawn, (avoiding the pool and coming to rest over the garden gnomes),
hurricane winds, hailstorms,
ambiguous and contradictory road signs,
unmarked roads,
interstate highway pileups,
white-out snow conditions.
I'm pretty sure your going to need pretty strong AI for all this to happen. By then we shouldn't be needing to go to work because everyone on earth can go on vacation and the machines will do everything that needs to be done. AND all this equipment has to be less expensive then hiring someone to drive around on your behalf.
Naysaying aside, self driving cars will cause a revolution in how cars are used, the concept of "owning a car" will disappear and then single passenger cars will fill the roads instead of 4 door seudans/SUV's.