When did people begin to refer to the "Ridge Route" as "The Grapevine?" (former US Route 99 and Interstate 5)
Attempting determine the origin of "The Grapevine" nickname to Interstate 5
Attempting to understand where "The Grapevine" nickname requires some background in Southern California slang and historic context on the Los Angeles-Bakersfield highway corridor. In Southern California slang "The" is often placed front of a name or agency in day-to-day vocabulary. Some common examples would be "The 405" denoting Interstate 405, "The CHP" denoting California Highway Patrol and in the case of this blog "The Grapevine" referencing a segment of Interstate 5.
In 1772 during the period of Alta California acting Spanish Governor Pedro Fages was seeking an inland short cut between San Diego and Monterey. During the expedition a canyon was discovered which had numerous grapevines growing naturally within its walls. This canyon as subsequently named "La Canada de Las Uvas" which roughly translates into "Canyon of the Grapes." Today "Grapevine Canyon" is located what is now on Interstate 5 within Kern County a short distance north from Tejon Pass.
Eventually the corridor over Tejon Pass would become what was known as "El Camino Viejo." Although travel through Grapevine Canyon wasn't infrequent the more popular route was San Emigdio Canyon due to it lining up more directly with western San Joaquin Valley and being a shorter route to Corral Hollow Pass. The path of El Camino Viejo largely was aligned west of Tulare Lake and a rough modern analog can roughly be found in the form of California State Route 33 (CA 33).
After California had become an American State the existing alignment of El Camino Viejo was still in use as an inland overland route. By 1853 gold claims were struck along the Kern River which led to the Kern River Gold Rush. At this point the entirety of the Sierra Nevada Range had become attractive for prospectors looking to make money on the new mining claims. El Camino Viejo being routed west of the Tulare Lake watershed was suddenly no longer a viable route for the majority of travelers through San Joaquin Valley. A new route from Stockton to Los Angeles following the Sierra Nevada Foothills along the eastern edge of San Joaquin Valley known as the Stockton-Los Angeles Road was subsequently. In San Joaquin Valley the path of the Stockton-Los Angeles Road followed the general path of CA 65, particularly north of the Kern River.
Originally the Stockton-Los Angeles Road utilized an established path from San Joaquin Valley south over the 5,285-foot Old Tejon Pass in the Tehachapi Mountains to Antelope Valley. At the time Old Tejon Pass was simply known as "Tejon Pass" and was an ancient Native American Trail used to traverse the Tehachapi Mountains.The planned alignment of LRN 4 from Fresno to Los Angeles can be seen on the May 1913 California Highway Bulletin. The selected route between Bakersfield and Los Angeles is shown as a plotted projection. A rejected proposed route via Tehachapi Pass and Lancaster is also displayed. The survey for what would become the Ridge Route was ordered on January 25th, 1912.
The May 1913 California Highway Bulletin details reasonings for the then named "Tejon Route" being chosen over the alternate route through Tehachapi Pass and Lancaster. The primary reasoning for the Tejon Route being chosen was the 60 miles savings by taking a more direct route from San Fernando north to San Joaquin Valley via Castaic Ridge. Easier grades over the Tejon Route compared to Tehachapi Pass, better access to land for development, better drainage grades, and fewer bridges being needed are all cited as reasons that the Tejon Route ultimately was the favored alignment of LRN 4. Notably the survey photo does refer to the Los Angeles-Bakersfield segment of LRN 4 as the "Tejon-Castaic Ridge Route."
Confusingly the accompanying article in the July 1916 California Highways & Public Works refers to the Los Angeles-Bakersfield segment of LRN 4 as the Castaic-Tejon Ridge Road, Castaic Road, Castaic Ridge Road and as Ridge Route.
The October/November 1933 California Highways & Public Works details the opening Ridge Route Alternate between Castaic and Gorman. The Castaic-Gorman segment of Ridge Route Alternate opened to traffic on October 29th, 1933. The article notes Ridge Route Alternate was a bypass of the more haggard segments of the orginal Los Angeles-Bakersfield Ridge Route corridor.
The final upgrade to the Old Ridge Route in Grapevine Canyon was between Lebec and Fort Tejon which opened on August 31st, 1936, according to the October 1936 California Highways & Public Works. The final Grapevine Canyon Grade upgrade is stated to be part of the extension of Ridge Route Alternate and the final replaced segment of the older Ridge Route. The article stub does reference Grapevine Canyon as "The Grapevine" in numerous paragraphs. This appears to be the first reference something resembling the modern nickname "The Grapevine" in any official state sourced document. It is unclear if author R.M. Gillis coined the term "The Grapevine" or if it was already in use as a local nickname for the Ridge Route in Grapevine Canyon.