Vehicle-to-X (A generalisation of vehicle-to-vehicle communication) https://en.wikipedia.org/wiki/Vehicle-to-everything

The system exists but nobody is buying it. Probably because if your car has it first, there will be no other cars to talk to.

https://www.google.com/search?client=firefox-b-d&q=car+v2x

That works if every car has the same communication mechanism and is honest and nobody interferes and everybody's semantic understanding of the messages is the same.

As long as it is there just to improve safety. But it should not be relied on.

In other words, if you 'hear' "don't go", you don't go. But if you don't hear anything, it still doesn't mean it's safe to go, so you'll have to rely on something else. And if you are doing that anyway, is the added complexity worth it?

It certainly will be, once the ocean is boiled = as soon as self-driving cars begin to comprise a significant percentage of cars on the road.

This, in the long run, is a selling point that seems to be missing from most discussions in this comment section.

I can't communicate "telepathically" with fellow human drivers.

We tried it, but people kept on using it only to say the most innovative curse words at each other... Hah. :P