I know in some places (EU) and maybe even some American states that law does exist, however judging by the truck and the cop car this image was taken in the south. In my home state of Georgia the only requirements to register a vehicle are two headlights, two taillights and turn signals on the front, back and rear. That's literally it. I have actually seen boats driving down the road sitting on top of a truck chassis. In fact those rules get even more lax if the vehicle only has three or less wheels in which it only needs 1 light and 1 brake with turn signals in the front and back.