I once heard a story about a man who was confused about cruise control. He bought an RV, got on the open road, and when he grew sleepy he turned on the cruise control and headed for bed. A University of Michigan physicist has come up with a new type of cruise control that actually does give more driving duties to computers (although not enough to allow the driver to catch some z’s). Adaptive cruise control (ACC) could help rescue commuters from gridlock: Adaptive cruise control (ACC), as its name suggests, is a modified version of traditional cruise control. It employs radar to monitor the road ahead of a vehicle, automatically adjusting that vehicle’s speed to maintain a safe distance from the one in front. This is safer than manual driving because it reduces the system’s reaction time from nearly a second (human) to practically instantaneous (machine), thus helping to forestall shunts. But ACC may have a useful side-effect, arising from the fact that another effect of slow human reaction times is to produce traffic jams on apparently open roads. The beauty of it is that it speeds up traffic even if only a small percentage of drivers have it: In a recent paper published in The American Physical Society’s Physical Review, [physics Professor L.C.] Davis demonstrated a “spectacular” reduction in single lane jams if just 20 percent of the vehicles in a 600-car platoon were equipped with ACC. Technology can also help relieve congestion by allowing more of us to simply stay home.