1. The department of transportation shall mark the primary routes of all national historic trails including, but not limited to, the Pony Express Trail, Trail of Tears, Lewis and Clark Trail, Mormon Trail, Santa Fe Trail, Oregon Trail, and California Trail in Missouri, as described in the respective National Park Service comprehensive management and use plans, when published and distributed for each of the trails, by placing official National Park Service approved signs in locations where the trails travel on public highways and cross public highways. In addition, the department of transportation shall at such time as it shall mark the Santa Fe Trail place suitable signs at appropriate locations recognizing the contributions of Franklin and Arrow Rock, Missouri, to the origins of the Santa Fe Trail.

2. The state highways and transportation commission may accept and administer gifts and donations to aid in obtaining suitable signs bearing the proper approved inscription.