From the junction of interstate highway 135 with interstate highway 70, south on interstate highway 135 to the southern boundary of Saline county is hereby designated the Ben E. Vidricksen highway. The secretary of transportation shall place signs along the highway right-of-way at proper intervals to indicate that the highway is the Ben E. Vidricksen highway, except that such signs shall not be placed until the secretary has received sufficient moneys from gifts and donations to reimburse the secretary for the cost of placing such signs. The secretary of transportation may accept and administer gifts and donations to aid in obtaining and installing suitable signs.