We are all familiar with traffic jams in the middle of nowhere. There are no exits, merges, or hills to blame; it's just from the way car spacing is adjusted by drivers. Same thing after an obstruction has been cleared from the road but the traffic jam lasts for another hour as starting up is soon followed by brake lights again. TACC ought to be a good workaround, at least if there were a dedicated lane for TACC-equipped vehicles. Anyone know the literature on this? What percentage of vehicles equipped with TACC does it take to make a lane flow smoothly? Is anything added by a local-area network to coordinate a string of cars?