From the junction of United States highway 160 with United States highway 83, then west on United States highway 160 to the Kansas-Colorado border is hereby designated the Spanish-American war veterans memorial highway. The secretary of transportation shall place signs along the highway right-of-way at proper intervals to indicate that the highway is the Spanish-American war veterans memorial 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 and an additional 50% of the initial cost to defray future maintenance or replacement costs of such signs. The secretary of transportation may accept and administer gifts and donations to aid in obtaining and installing suitable signs.