I've noticed that when significantly reducing the set speed on the cruise control (eg when coming into a 50 limit on the motorway) by holding down the stalk, the car slows fairly quickly, as though the brakes have been applied rather than just lifting off the throttle. I've often wondered whether this also triggers the brake lights to warn other drivers of the fairly rapid deceleration but, without having someone follow me and watch, I've no idea if this is the case. I just wondered if someone on here might know?