Most automatic cars available might already be moving at very slow speed once u take your foot off the brake after moving them into gear (provided you are on level ground). I can see the reason for such a low speed cruise, but frankly, most people are harried about others cutting into their lanes if they keep anything over 10-12 feet between them and the car in front. cruise control switches off when u hit the brakes and i think most of your time in traffic is spent alternating between the gas and brake pedals. only a car that would drive 'at all times' based on such a safety distance programmed into it, would be able to function like this. this system should enable one to vary the safety distance depending on the speed and driving conditions around them. Maybe this historical data would help cops determine who wasn't following safe driving practices (lower than mandated safety distance at the speed the car was driving at). Again, this might give rise to lawsuits against car companies because drivers are too silly to figure out the system and to use it intelligently. hey, we have a manual system of checks and balances which a lot of people have not figured out yet (turning lights, anyone?!).