N.H. Rev. Stat. § 266:40
Every bus, motor truck, trailer or semi-trailer, having a width including load in excess of 80 inches, when on the ways of this state at night, shall have displayed on the front thereof, in addition to the front lights provided for in RSA 266:31, 2 amber clearance lamps. Every such vehicle shall have displayed on the rear thereof, in addition to the tail lamp and reflectors provided for in RSA 266:44, 2 red clearance lamps. All clearance lamps shall be located on the permanent part of the body, as high as possible thereon, one at the extreme left and one at the extreme right, to indicate the extreme width of said vehicle and load. Those on the front shall be visible, when lighted, for a distance of at least 500 feet from the front and the side and those at the rear shall be visible, when lighted, for a distance of at least 500 feet from the rear and the side, of said vehicle. However, in the case of vehicles and loads in excess of 45 feet in length, the rearmost clearance lamp arrangement shall be mounted on each side of the rearmost support for the load, one combination marker lamp showing amber to the front and red to the side and rear, mounted to indicate the maximum width of the vehicle and load. Said clearance lamps shall be of such type, size and color as shall be approved by the director.
RSA 266:40
1933, 134:1. 1941, 111:3. RL 119:9. RSA 263:17. 1981, 146:1, eff. Jan. 1, 1982.