It shall be the duty of the governing body of any municipality, at or before the time any such bridge shall be acquired by such municipality by purchase or by condemnation, to determine what repairs, replacements, additions, or betterments will be necessary to place the bridge in safe and efficient condition for the use of the public, and to cause an estimate of the cost of such improvement to be made. The governing body of the municipality shall authorize such improvements before the sale of any bridge revenue bonds for the acquisition of such bridge, and the cost of such improvements shall be paid for out of the proceeds of such bonds.