a route from US 101 near Santa Margarita to the Nevada state line via Bakersfield. Construction on the route between Bakersfield and Isabella through Kern Canyon started in 1922. Progress moved slowly, as sheer rock walls had to be blasted with dynamite. In 1931, 9 years after construction started, the 26-mile highway segment was completed. In 1933, with the creation of signed routes, portions of LRN 57 and LRN 58 would be signed as Route 178. LRN 58 would be signed between Route 33 and US 99, and LRN 57 would be signed between US 99 and US 6. Later, in 1947, LRN 212 was created, and defined to run from LRN 23 (signed as US 6) near Inyokern, east to the Nevada state line. It was an unsigned route. From 1950 to 1953, a portion of SR 178 in Lake Isabella was rerouted around the Isabella Auxiliary Dam. The dam was built over the old route and parts of it are inundated by Isabella Lake. The new route goes over the dam's southern abutment and along the shoreline of Isabella Lake toward Onyx. In 1964, all of the California routes were renumbered. LRN 58 was dropped from Route 178 and combined with the eastern portion of the decommissioned US 466 (also defined as part of LRN 58) to create SR 58. The remaining Route 178 was combined with LRN 212 to create SR 178. It was originally defined to start at SR 99 in Bakersfield, but later that year it was changed to simply start in Bakersfield. This change was probably done to avoid a cosign with SR 58 along 23rd/24th St. After SR 58 was moved to the freeway south of Brundage Lane in 1976, SR 178 was extended west to SR 99. Construction on the initial freeway in Bakersfield was completed in 1968. It ran from M St, on the eastern edge of Downtown, through East Bakersfield to Haley Street. Eastern extensions have been constructed since 1968, one interchange at a time as the need arises. In the Kern Canyon section, which is between Bakersfield and the Kern River Valley, a bypass route was identified in 1964. By 1968, a deed from the US Forest Service issued an easement to the State for the construction of the highway through National Forest lands. The first phase of construction was completed in 1974, which created a short freeway near