8" backup camera screen aren't required. I've seen some as small as about 4". The standard requires only that a certain spacing/size of objects behind the car i

8" backup camera screen aren't required. I've seen some as small as about 4". The standard requires only that a certain spacing/size of objects behind the car is at least a certain visual angle. Screens in rear view mirrors and just below the bottom edge of the windscreen abound.