The provisions of §§ 33.2-300 through 33.2-305 shall not become effective with respect to those segments of the Interstate System constructed and financed as toll projects until the revenue bonds and the interest thereon issued on account of such toll projects have been paid or a sufficient amount for the payment of all such bonds and the interest to maturity thereon has been set aside in trust for the benefit of the respective bondholders. When the bonds and interest thereon, outstanding on account of such projects, have been paid or a sufficient amount for the payment of such bonds and the interest thereon to the maturity thereof has been so set aside in trust, and when the Board has by formal action, recorded in its minutes, determined the existence of such fact, then the provisions of §§ 33.2-300 through 33.2-308 shall fully apply to such projects.