[lsaferite]

Actually, if everyone perfectly tailgated out of a rolling jam, then they'd all be fine. Instead you get people that let a large enough gap open for them to accelerate faster than the car in front, then they have to brake when they reach that lead car again. This slinky effect is what causes those rolling traffic jams and why they can break them by slow-rolling in from of the jam to force everyone to stop the slinky effect.