(a) The portion of Interstate Highway 45 in Montgomery County between its intersection with State Highway 242 and the Montgomery-Harris county line is designated as the George P. Mitchell Memorial Highway.
(b) Subject to Section 225.021(c), the department shall:
(1) design and construct markers indicating the designation as the George P. Mitchell 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.