N.D. Const. art. X, § 11

Revenue from gasoline and other motor fuel excise and license taxation, motor vehicle registration and license taxes, except revenue from aviation gasoline and unclaimed aviation motor fuel refunds and other aviation motor fuel excise and license taxation used by aircraft, after deduction of cost of administration and collection authorized by legislative appropriation only, and statutory refunds, shall be appropriated and used solely for construction, reconstruction, repair and maintenance of public highways, and the payment of obligations incurred in the construction, reconstruction, repair and maintenance of public highways.