>This kind of rapid-slowing situation in tight-fast traffic will likely even get out of hand even for automated cars, unless there is car-to-car communication.

>This kind of rapid-slowing situation in tight-fast traffic will likely even get out of hand even for automated cars, unless there is car-to-car communication. This is because of the slight delay for each successive slowing car in the accordion-effect accumulates to the point where eventually the required reaction time decreases and required deceleration rate increases past the performance envelope. At that point, a crash is inevitable. Is this really true? It seems like, as long as the following delay between cars is greater than that reaction delay, there should be no such "accordion effect."