We are getting waaaay out in front of our skis. There is a LOT to discuss about autonomous cars:
First point is that by far the best autonomous cars are ELECTRIC. So, if we see a lot of autonomous cars - most of the cars on the road will be electric.
Second point is that before we see Level 5 (FULL autonomous) cars, we will see MOST cars with Level 2, or Level 3 STANDARD.
Third point: autonomous cars need to be "learning" - and therefore they have to A) "talk" to each other, and B) they need to share ONE DATABASE.
Fourth point: we can barely get this to work on LIMITED ACCESS highways, that have bright painted lines. Making the jump to full autonomy on ALL KINDS of roads / highways, in ALL conditions - is a QUANTUM increase in complexity.
To illustrate this fourth point: take a gaming computer - these are right at the cutting edge of performance - and ALL it has to do is render a PRE-MADE 3D MODEL. An autonomous car has to take the inputs from 8-12+ different sensors - and it has to "build" a moving 3D model, AND it has to do all the vectors of their motion - a FOURTH DIMENSION - in the blink of an eye.
AND it has to PRIORITIZE ALL THE MOVING OBJECTS that it "sees".
AND it has to "decide" the best route, AND the second best route, AND MAYBE even the third best option - CONSTANTLY.
Fifth point - it probably needs to have a FULLY REDUNDANT set of backup hardware - AND / OR it needs a really robust "algorithm".
Sixth point: WHO IS LIABLE FOR WHAT THE CAR DOES?
Seventh point: in what world will our government have a consistent and effect set of regulations? The insurance companies have to be onboard, too.
To sum up - we first will have to have a majority of cars on the road to be electric, and we will have to have a majority of cars / vehicles to have automatic safety function, that backup the driver - as STANDARD equipment.
Then, and only then - we will need a shared open source database of all / most cars, so that each vehicle gets as much advantage as possible - of driving in any / all conditions as close to perfect as possible.
The goal is - obviously - much better vehicle safety. Lets be realistic about how / when this can happen.
Predetermined routes is an important step. And the driver's role is wholly transformed - they go from being 100% responsible, to being a passenger.
And how do we enter the desired route? Have you gotten 100% accurate GPS routes, all the time?
People WILL do these things - and more - in their moving cars:
Watch a movie