Upon and after the date on which the International Fuel Tax Agreement of July 1987 becomes effective, every person who holds a valid license issued by a member jurisdiction of the agreement shall be subject to the provisions of the agreement, which provisions shall prevail in the case of any conflict with the provisions of this chapter or the Special Motor Fuels Tax Law, § 26-56-101 et seq. Provided, however, that for all persons other than those holding a valid license issued by a member jurisdiction of the International Fuel Tax Agreement of July 1987, the provisions of this chapter and the Special Motor Fuels Tax Law, § 26-56-101 et seq., shall be and remain fully applicable.