N.H. Rev. Stat. § 266:45
Every bus, motor truck, and every trailer and semi-trailer, provided the weight of said trailer or semi-trailer, including load, is 3,000 pounds or more, shall in addition to reflectors required in RSA 266:44, when driven upon the ways of this state at night, have displayed on the body or load carrying portion of said vehicle, the following: on each side one amber reflector, located at or near the front, and one red reflector located at or near the rear. Such reflectors shall be of such a type and size as shall be approved by the director and shall be located not less than 24 nor more than 48 inches from the ground. The visibility of any such reflector shall not be impaired at any time.
RSA 266:45
1935, 44:1. 1941, 111:4. RL 119:10. RSA 263:19. 1981, 146:1, eff. Jan. 1, 1982.