sentences:  By the mid-1920s, the entire route had become an extension of the Abo Pass Highway, and was SH 33 along the entire length.In 1928, the AASHO added the highway to the U.S. Highway System as U.S. Highway 164, with the Texas section being signed in 1929.It was renumbered as US 60 on June 8, 1931, when the route was extended to Los Angeles, California to make it a coast to coast highway.