This thread is not about the lack of Adaptive Cruise Control, which has been amply discussed. Instead, I'd like to focus on what changes Tesla could make in software to improve the existing cruise control. My biggest complaint with the current implementation is the transition from CC on to CC off: In ICE vehicles, turning off the CC puts you into "coast," i.e. neither the brake nor gas is applied. I like this result; it gently slows the car, so I can match the speed of the car ahead of me if I'm gaining on it. In the Model S, turning off the CC throws the car into full regen braking, with the brake lights on. I can see why Tesla did this; like in an ICE, it's just transferring the inputs from the computer to your feet. The difference is that, in an ICE, if your feet are off the pedals, you coast; in a Model S, you regen. To effect a smooth transition, you have to get your foot on the accelerator and find the "match point" where, when you flick off the CC, you'll have no change in speed. This is not easy, and it's not fast. My suggestion is that the regen should be limited shortly after you turn off the CC. For the first second, allow the car to coast (0% regen). Over the next few seconds, increase the regen limit, so that by, say, four seconds you have full regen again. This would give the driver time to gracefully transition over to manual control.