Keep your distance.

Active Cruise Control on the BMW 3 Series Sedan.

A long straight on the freeway. The BMW 3 Series Sedan is cruising at a constant speed. It approaches a slower car in the lane ahead, and automatically ACC reduces the Sedan's speed. When the car ahead clears the lane, the Sedan returns to its previous speed - all without demanding the driver's attention. A short touch on the accelerator immediately disengages the system.