There are basically two auto cameras, one is used for night vision like the one provided in new Land Cruiser. The other is rear view camera.
Night vision camera may be good in cars for people bad eye sight. But rear view cameras are only useful for heavy vehicles, like big 4x4, vans, trucks, RVs, busses, where you can not precisely judge the distance of things in the back of your vehicle.
http://www.lightav.com/car/crime/backup.html
http://www.astralelectronics.com.au