(a) Notwithstanding Section 225.001(c), the portion of U.S. Highway 75 in Collin County between its intersection with the President George Bush Highway and its intersection with U.S. Highway 380 is designated as the Sam Johnson 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 Sam Johnson 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.