[sandworm101]

But my point still stands. If you are letting the machine set your speed according to the car ahead, what if that car's speed is not appropriate for you? Does the machine make a judgement as to the performance abilities of the car ahead? Humans wouldn't follow as close to a Porsche as they would a truck. You don't want to be too close to something that can stop far faster than you can.

If the adaptive cruise control is staying far enough away that it can always stop that is an entirely different problem. Leaving so much distance, so much empty road, between cars reduces the total carrying capacity of the lane, which isn't good for anyone.