Cars and non-drivers.
There's a bit of a problem coming up though with autonomous cars... The current thinking by commenters and possibly even the engineers is that one gets in, sits behind the wheel, gets comfortable and assumes a driving position while the car does all the work. Just in case the driver needs to take over... right? Complacency will soon wipe that idea out as more and more drivers decide to text, read a book, play with the kids or spouse, eat, or whatever. Having a steering wheel could become the hazard.
This is the difference between cars and airplanes. Pilots still have be in the cockpit and monitoring. They're not supposed to be wandering about and doing other things.. yeah.. there's been reports such as the one where the plane flew right past the destination airport.
My guess is that after an initial break-in, the controls will have to be removed from the car and allow it to be fully autonomous. Driver skills will deteriorate after a period of non-use and I'm wondering about having someone suddenly grabbing control of the car when their ability has deteriorated. Seems to be it has to be an all or nothing on autonomy.