N.H. Const. pt. 2, art. 6-a

All revenue in excess of the necessary cost of collection and administration accruing to the state from registration fees, operators' licenses, gasoline road tolls or any other special charges or taxes with respect to the operation of motor vehicles or the sale or consumption of motor vehicle fuels shall be appropriated and used exclusively for the construction, reconstruction and maintenance of public highways within this state, including the supervision of traffic thereon and payment of the interest and principal of obligations incurred for said purposes; and no part of such revenues shall, by transfer of funds or otherwise, be diverted to any other purpose whatsoever. November 29, 1938