I think it could help solve congestion as a problem too.
Maybe cars could book their routes, and the road brokers will maximise for #cars/destination instead of allowing people to keep piling in even after the useful capacity is exceeded.
That would probably be the hardest problem to solve, and it would require global cooperation, but yeah it would also be a nice end-goal.
Cooperation would already go a long way to solving congestion with just local cooperation though:
* higher road density (cars can pretty literally travel bumper-to-bumper)
* better handling of congestion (car train can smooth local slowdowns over all its component cars)
* much, much improved merging and splitting of roads (including local flow analysis e.g. a small road merging into a bigger interstate with a 3:1 traffic ratio could be managed into a "perfect" 3:1 merge frequency)
* simplified urban planning (if only cooperative automated cars are on the road, you can get rid of red lights)
You can only get rid of red lights if you don't care about pedestrians. I hope automated cars don't lead us to exacerbate the car-centric city problem we've built for ourselves.
