The function took some getting used to. After setting the system to maintain a distance of about 170 feet from cars in front of me, it took a lot of nerve not to apply the brake manually when I was humming along at over 90 mph and saw that traffic had come to a dead stop just a few hundred feet away. But in time I learned to trust the Distronic system enough to force myself to keep my feet flat on the floor while the car gently decelerated from high speeds to a dead stop -- without plowing into the car ahead of me.
The feature is, um, designed to maintain a safe distance between you and the MOVING vehicle in front of you, not to execute panic stops from...90 mph.
For anyone who flunked physics, here's this from AutoTrader.com:
Of course the faster you go, the more time and distance it takes to stop. For example, at 70 mph, perception and reaction distance equals 154 feet, and braking distance equals 188 feet, for a total of 342 feet (5.2 seconds). And we won't even talk about 80 mph and above, since our readers are law-abiding citizens who never break the speed laws. It wouldn't interest you to know, for instance, that at 80 mph it takes over 422 feet (5.7 seconds) to bring your vehicle to a halt, and at 90 mph more than 509 feet (6.2 seconds) -- nearly a tenth of a mile.
Makes you wonder how the car "gently decelerated."
