I’m sure that as the technology advances these cars can be joined together through WiFi and communicate with each other.I think 1 problem with self driving cars is they are driving next to a human driver and it can't calculate a human response.
So it wouldn’t be a stretch to say that even a car that is being drivin by a person could communicate in real time all sorts of things.
Breaking, speed, the steering could also be communicate so as quick as a person turns the wheel it could tell all the cars around it what it’s doing instantly.