06-01-12, 07:04 PM
The older style cruise controls just operated the throttle so if you started to speed up due to a hill, it would close the throttle to slow you down. If it still went too fast even on a fully closed throttle then it simple went too fast. The more complex ones actually operate on the brakes as well so that won't happen. I drove an SL55AMG Merc last year and that had the cruise control, traction control, ABS and anti-collision system all linked. If you went beyond the set speed on the cruise control and shutting the throttle didn't get you speed down enough, it would apply the brakes. In the same way, if you had the anti-collision switched on and got too close to the car in front it would also put the brakes on for you to maintain a safe distance.