I don't see that scenario happening with driveless cars, where each and every one of them are programmed to react to the same stimulus in the same fashion, and

I don't see that scenario happening with driveless cars, where each and every one of them are programmed to react to the same stimulus in the same fashion, and are perfectly aware of how the other cars would react. I wonder if, with time, some kind of secondary radar system for cars will arise. If everyone was forced to have one in the car (as happens with planes), the mixing of driveless cars with regular ones would be greatly eased.