For many years I have wondered why cruise controls in vehicles did not include a braking function that would be able to maintain speed when going downhill or being impeded by multilane traffic. Well, it appears Bosch, TRW, Delphi, and others already thought of that and have solutions in their Adaptive Cruise Control (ACC) systems. This particular video is of the Bosch system. A mm-wave radar unit measures distance and relative speed to feed data to the microprocessor that determines when to apply the brakes or when to give it the gas. ACC is smart enough to compensate for rapidly varying traffic speeds, as well as for lane changes and even going around corners. An ability to monitor vehicles in multiple lanes is incorporated into it decision making. High-end auto makers like Lexus, Audi, Mercedes, et al, have been offering it for a few years. The low-end heaps I can afford are still waiting for a price reduction; I will be tapping the brakes and mashing the Resume button myself for many more years.