(a) The portion of State Highway 315 in Panola County between its intersection with the western Panola County line and its intersection with the western municipal boundary of Carthage is designated as the Hamby-Webb Memorial Highway. The designation is in addition to any other designation.
(b) Subject to Section 225.021(c), the department shall:
(1) design and construct markers indicating the designation as the Hamby-Webb Memorial Highway and any other appropriate information; and
(2) erect a marker at each end of the highway and at appropriate intermediate sites along the highway.