Today, I drove to Blaine WA and back - about 560 miles or so total, 10-11 hours on the road. Really, the only exercise I got was stretching at the roadside rest stops. Apple Watch correctly counted exercise as 0 minutes. However, it did count 'movement' while driving, to the tune of 999 calories by the time I returned. Here's a screenshot from mid-afternoon, at the halfway point. I did have the phone with me, so I'm not sure which one was picking up on the movement in the car. I think the algorithm needs to discard any movement detected at freeway speeds.