@jwz Self-driving cars are an all or nothing solution since driving is complex and for self driving cars to work an unpredictable human can't be behind the wheel in any other vehicle on the road with it.
You know what can work though, self-driving trains. Since trains are on rails which are controlled by track switching devices, the train engine itself really only needs to accelerate, decelerate, and brake.
So it's not inconceivable to think this could be somewhat automated in the future.