i have seen tons of people here in colorado with backup light systems on their roof rack uncovered.

i also have been followed on the road (just normal driving) by cops before, and havent been pulled over for it.

the only law that i know of (at least in colorado) is that you can only have 2 sets of lights on at one time on the road (ie fog, and normal lights).

if i were to turn the rear lights on while driving, it would be very illegal im sure.