I was driving in the right lane on a four lane interstate highway with good driving conditions and a 70 mph speed limit. the car was an enterprise rental. adaptive cruise control uses the accelerator and brakes to maintain a safe distance to the car ahead. it is done by sensing the distance to the car ahead at about 5 car lengths then adjusting the accelerator and brakes as needed to maintain this spacing and avoid a rear end collision. the fault is seen in changing lanes. the cruise was set at 70 mph and my car approached a car ahead going 65 mph. my car's adaptive cruise decelerated to 65 mph. i steered into the next lane, and the space was not the requisite 5 car lengths, the car sensed a car closer than 5 lengths reducing my speed to less than 65 mph. my car was now slowing down below 65 mph in a lane with cars going 70 mph. i pressed on the accelerator, accelerating to 70 mph, avoiding a rear end collision. enterprise did not inform me of the adaptive cruise features and operation. there was no warning sticker in the car stating: "turn off cruise control when changing lanes."