I had one on the back of the truck, one inside that I could see 100% of the cargo with the 0lux led setup and one on the back of the trailer up top so I could back up or see traffic. They make models like the RV setups for the side of the trailer for lane changes. I can hook 4 video sources to the multiplexer they provided but they make larger setups. If you are really looking for total coverage/visibility from the cab, this works but its not the cheapest solution.