Not much would change. The idiotic idea of removing traffic lights in favor of self driving cars zipping past each other forgets about those pesky pedestrians we should be designing cities for.
When I wrote the comment, I was envisioning the current world, but with some bluetooth type protocol that cars could use to send beacons to help other cars near it.
The most basic example of how this could be helpful is if the car ahead of you turns a sharp corner and crashes into a truck stopped in the road. Without car-to-car networking, you won't brake until the crash is in your line of sight.
Have you ever seen those youtube videos of massive car pile ups on highways caused by a crash, and then a cascade of additional crashes afterwards? E.g. icy conditions or dense fog. What if the original crash could communicate to cars behind it, wouldn't that be helpful if the crash isn't yet in the driver's (or car's) line of sight?
I agree "not much would change" overnight. It's just another input for the car's software to have at its disposal.
With the current hardware on the roads, I don't think it's technically possible for autos to achieve legitimate self-driving (if that's even the goal anymore?) - there are way too many edge cases that are way too difficult to solve for with just software.
