I really don't think that in the future, cars will be individually fully autonomous. I think that cars will form groups or networks depending on where they are, a group is a horde of cars with one "mind" and THIS is what's going to be fully autonomous.
With the help of the internet and sensors, all cars of a network will go at the same speed, keeping the same distance between each others.
Cars of a network will be in a snake formation, so as soon as a car detects a moving object that they identify, all the cars will slow down at the same speed, stop, or the line (the group) can be split in two if an object cut it, the whole line also be led by the first car into doing an S to avoid an obstacle on the road. Imagine, you will be able to cross the road as a pedestrian without even looking and the entire line of cars will slow down at the same speed or split, the "flow" will adjust perfectly.
Also, if a car comes from an overpass and wants to fit into the group that is tacking the line on the highway, the group will immediately adjust the speed and split so the car can have a place in the line.