I've just bought an in car camera, a RoadHawk DC-1. It sits behind the mirror and records GPS information plus sound and video onto an SD card. It has a shock sensor that makes it save data as an event should it detect a sudden movement. This means that it is stored in a different section of the card. I went out for a little test drive and someone pulled out on me. If I had been another 20 feet further down the road he would have hit me. Maybe it's jinxed, in which case it's not such a good idea.