(a) State Highway 121 between Interstate Highway 30 in Tarrant County and United States Highway 67 in Johnson County is designated as the Chisholm Trail Parkway.
(b) The department shall design and construct markers indicating the highway number, the designation as the Chisholm Trail Parkway, and any other appropriate information.
(c) The department shall erect a marker at each end of the highway and at appropriate intermediate sites along the highway.