Sec. 7. (a) A county may, in anticipation of the construction of a bridge, make and enter into a contract of lease with the lessor corporation subject to the approval of the department of local government finance prior to the actual acquisition of a site and the construction of the bridge, but the contract of lease shall not provide for the payment of any lease rental by the lessee until the bridge is completed and ready for use, at which time the stipulated lease rental may begin.
(b) As a condition of entering into a lease, a county may require a lessor corporation to furnish a bond in a specified amount conditioned upon the completion of the bridge within a specified period of time.