I was driving on a high-speed oval test track in suburban Detroit. It was not the sort of road where one worries about plowing into a car stopped on the road. But suddenly my S class seemed to be hurtling toward a certain finish deep within the trunk of a car ahead.
Then Mercedes' specialized cruise control from supplier Continental AG kicked in.
A radar sensor in the front grille had "seen" a rapidly closing object. A set of video cameras then verified that it was a car, not just a tin can or piece of road debris. Signals flashed through the car's computer network to preload the brake system, arm safety systems and warn the driver with an instrument panel display.
Because I didn't react, the S class first slowed, then stopped by itself a short distance behind the other vehicle. After the lead car moved off, I pushed on the accelerator pedal. That re-engaged the cruise control to take us gradually back up to highway speed.
This is the future for so-called advanced adaptive cruise control, or ACC. Last year it began entering the market on European luxury cars. In addition to the S class, systems from supplier Robert Bosch GmbH have been available on the Audi Q7 and BMW 5 series.
Adaptive cruise control will maintain a certain distance from the car in front, down to a crawl. The advanced form of the technology will bring the car to a stop. It also can resume its cruise control functions from a stop.