The portion of Interstate Highway 55 from its interchange with U.S. Highway 61 at exit 170 continuing north to the point at which U.S. Highway 61 overpasses Interstate Highway 55 in Jefferson County shall be designated the “USMA Cadet Thomas M. Surdyke Memorial Highway”. The department of transportation shall erect and maintain appropriate signs designating such highway, with the costs to be paid by private donations.