August 23, 1963 —
Under the freeway overpass at Red Rover Mine Road in Acton, Los Angeles City Mayor Sam Yorty speaks at the grand opening ceremony for the first stretch of the Antelope Valley Freeway.
This first section stretched from (east of) Solemint Junction in Canyon Country to Red Rover; the day's event began with the opening of the highway at Sand Canyon as seen here.
Apparently the Los Angeles County Department of Parks and Recreation provided the temporary staging. L.A. County Supervisor Warren Dorn is sitting behind Yorty (there's a white splotch, probably a piece of paper, in front of Dorn).
Seated in front, the second beauty queen from the left is 15-year-old Bonnie Dillenbeck, 1963's Miss Tri-Canyon (Mint, Sand, Soledad).
Born in December 1947, Bonnie Dillenbeck, later Bonnie Jones, is the third of six children of Charlie and Gertrude (Powell) Dillenbeck, owners of Dillenbeck Canyon Market on Sierra Highway.
The Antelope Valley Freeway was built in sections from 1963 to 1975 as an upgraded bypass to old U.S. Highway 6 between Interstate 5 (initially US-99) at the Newhall Pass on the south and US-395 at Inyokern on the north. Locally, US-6 was known as Sierra Highway.
The first freeway section, from a point east of Solemint Junction (Soledad and Sierra) in present-day Canyon Country to Red Rover Mine Road in Acton, opened Aug. 23, 1963. Additional sections extended the freeway to the Soledad Pass (Vincent Grade south of Palmdale) in 1965, to Avenue P-8 in 1966, and to Mojave in 1972. The section from Mojave to Inyokern is called Aerospace Highway.
SR-14U. Photo 11-17-2013.
As of 1964, Sierra Highway lost its designation as US-6 and became State Route 14 — except from Solemint to Red Rover, where the new SR-14 freeway alignment had already been completed. After that, the SR-14 designation was transferred from Sierra Highway to the new freeway as each new section was completed.
Other parts of old US-6 south of Bishop became US-395, I-5, I-110 and SR-1 at Long Beach.
Within the city of Santa Clarita, one stretch of Sierra Highway was never fully decomissioned. As a result, Caltrans maintains the section of Sierra Highway from 500 feet north of Newhall Avenue to Whispering Leaves Drive, and it is the California Highway Patrol's responsibility to enforce traffic laws there.
This section bears the unusual designation of SR-14U, where "U" stands for "unrelinquished." The rest of Sierra Highway that's inside the city is a city street.
UPDATE: In 2017, the state Legislature approved AB 1172 (Acosta-Wilk), which clears the way for the relinguishment of SR-14U between Newhall Avenue and Friendly Valley Parkway
upon a future agreement between the city and Department of Transportation, without requiring further legislative action.
[DILLENBECK story in development]