RSA 266:44 Tail Lamp and Reflectors.

Every motor vehicle and trailer or any combination of vehicles, when on the ways of this state at night, shall have on the rear thereof, and to the left of the axis thereof, one lamp, displaying a red light visible for a distance of at least 1000 feet to the rear of such vehicle, and a white light illuminating the registration plate of such vehicle so that the characters thereon shall be visible for a distance of at least 50 feet, except that passenger cars manufactured or assembled after January 1, 1952, shall have at least 2 tail lamps, one to either side of the axis thereof. On a combination of vehicles, only the tail lamps on the rearmost vehicle need actually be seen from the distance specified. On vehicles equipped with more than one tail lamp, the lamps shall be mounted on the same