With the approval of the Department, a road district may use funds allocated under Section 6-901 for the payment of any indebtedness incurred after the effective date of this amendatory Act of 1976, in the construction of any bridge selected under Section 6-902 as a bridge to be constructed under Section 6-902 and the payment of engineering costs incurred in connection therewith; but if the road district desires to use such allocated funds for this purpose it shall follow the same procedure in expending moneys secured in the creation of the indebtedness as if the construction was to be paid for directly with funds under Section 6-902.