The purposes of the International Registration Plan Act are to:
(1) Promote and encourage the fullest possible use of the highway system by authorizing registration of fleets of apportionable vehicles and the recognition of apportionable vehicles apportioned in other jurisdictions, thus contributing to the economic and social development and growth of the jurisdictions;
(2) Implement the concept of one registration plate for one vehicle;
(3) Grant exemptions from payment of certain fees when such grants are reciprocal; and
(4) Grant reciprocity to fleets of apportionable vehicles and provide for the continuance of reciprocity granted to those vehicles that are not eligible for apportioned registration under the act.