There has been a recent trend to paint speed cameras bright yellow so that they can be seen easily and so act as a deterrent to speeding motorists. This is the exact opposite of what should happen. If cameras are obvious, drivers tend to drive very fast between them and brake hard when they see one ahead, which is a very dangerous practice. If cameras were virtually invisible, drivers would have to keep within the speed limits all of the time for fear of being caught unawares.