The authority is hereby authorized to provide by resolution for the issuance of turnpike revenue refunding bonds of the authority for the purpose of refunding any bonds then outstanding which shall have been issued under the provisions of this act, including the payment of any redemption premium thereon and any interest accrued or to accrue to the date of redemption of such bonds, and, if deemed advisable by the authority, for the additional purpose of constructing improvements, extensions, or enlargements of the turnpike project or projects in connection with which the bonds to be refunded shall have been issued. The authority is further authorized to provide by resolution for the issuance of its turnpike revenue bonds for the combined purpose of (a) refunding any bonds then outstanding which shall have been issued under the provisions of this act, including the payment of any redemption premium thereon and any interest accrued or to accrue to the date of redemption of such bonds, and (b) paying all or any part of the cost of any additional turnpike project or projects. The issuance of such bonds, the maturities and other details thereof, the rights of the holders thereof, and the rights, duties and obligations of the authority in respect of the same, shall be governed by the provisions of this act insofar as the same may be applicable.