I have adaptive cruise control on my Taurus, and it can be a great convenience when driving in medium-density interstate traffic. Basically I set it for the maximum desired speed and the radar adjusts speed accordingly when traffic looms ahead or fades away. It's even tied into the braking system, and can decelerate the car pretty sharply if a car changes lanes and cuts me off. The only thing that I don't like about this particular system is that it deactivates at about 25 mph, so there have been times when the car has been braking to maintain a gap; the car drops down to that speed, and the "son, you're on your own" chime dings to let you know that you're freewheeling towards that '73 Grand Prix just ahead of you. It makes texting, reading and picking your teeth while driving an iffy proposition. My car also has a lane-holding feature, but it's kind of "lane holding lite" - more attuned to letting a driver know that he's broaching the double line, than reliably keeping the car in the lane.