No moneys derived from fees, excises, or license taxes levied by the state and exclusive of registration fees and licenses or excise taxes imposed by a county or municipality, relating to registration, operation or use of vehicles on public highways, streets or alleys, or to fuels used for propelling such vehicles, shall be expended for other than cost of administering such laws, statutory refunds and adjustments allowed therein, payment of highway obligations, costs for construction, reconstruction, maintenance and repair of public highways, county roads, bridges, and streets, alleys and bridges in cities and towns, and expense of enforcing state traffic laws.