When all bonds and the interest thereon shall have been paid or a sufficient amount for the payment of all bonds and the interest to maturity thereon, shall have been set aside in trust for the benefit of the bondholders, and shall continue to be held for that purpose, the turnpike and the connecting tunnels and bridges shall become a part of the system of State highways, and shall be maintained by the Department of Highways free of tolls, and thereupon the commission shall be dissolved, and all funds of the commission not required for the payment of the bonds and all machinery, equipment and other property belonging to the commission, shall be vested in the Department of Highways.
36 P.S. § 652o