There’s no evidence that this sort of system is possible given the latency of wireless communications and probability of momentary glitches in real time systems long enough to cause a cascading set of failure leading to crashes.
Say the power cuts in a car, or worse its location updates no longer match the surrounding cars’ sensors, the cars in its mesh could immediately alert all the cars around that it is no longer updating its location and might be anywhere, so all cars in the area should go into low speed safe mode. It should be a doable to some degree.