California State Route 14

Antelope Valley Freeway through the San Gabriel Mountains, with California Aqueduct at Palmdale in the foreground

The southern portion of the freeway, from I-5 to the Avenue D exit near Lancaster, has been designated the Antelope Valley Freeway by the state legislature.[6] The Antelope Valley Freeway begins in the Santa Susana Mountains at the Newhall Pass interchange by splitting from the Golden State Freeway (I-5). This is the busiest portion of the route with an annual average daily traffic (AADT) count of 169,000 vehicles per day.[7] The freeway forms much of the eastern boundary of Santa Clarita along its route. Past Santa Clarita, the road continues northeast and crosses the Sierra Pelona Mountains and western San Gabriel Mountains via the canyon of the seasonal Santa Clara River. The ascent is mostly rugged and rural terrain, with only two small towns along the ascent, first Agua Dulce and later Acton. In Agua Dulce, the freeway forms the southern boundary of Vasquez Rocks Park, a county park. The highway crests the Sierra Pelona Mountains via Escondido Summit, at an elevation of 3,258 feet (993 m), before descending and passing by Acton to the north. The highway then crests the San Gabriel Mountains via Soledad Pass, at an elevation of 3,209 feet (978 m).[8] The route of the highway through the mountains loosely parallels that of the Metrolink Antelope Valley Line.[9][10]

After cresting both mountain passes, the highway descends into the Antelope Valley, a large valley within the Mojave Desert. The highway crosses Angeles Forest Highway and the California Aqueduct in the descent. SR 14 serves as the primary north–south thoroughfare for the communities of Palmdale and Lancaster. Between Palmdale Boulevard (County Route N2) and Avenue D in Lancaster, SR 14 runs concurrently with SR 138.[10]

From the Pearblossom Highway exit south of Palmdale to its northern terminus at US 395 near Inyokern, SR 14 has been designated the Aerospace Highway.[6] Between Pearblossom Highway and Avenue S, there is a vista point overlooking Lake Palmdale, which features a historic plaque that honors aviation accomplishments including the Space Shuttle, breaking the sound barrier and the speed record.[6] The freeway passes the Los Angeles–Kern county line at Avenue A, and continues to run north through Rosamond and Mojave. In Rosamond, the highway passes close to Edwards Air Force Base, which was often used as one of the main landing strips for NASA's Space Shuttle, and as the base for the X-15 and many other air and spacecraft.[11]

The freeway portion terminates just south of Mojave, where SR 14 serves as the main street and runs through the downtown area. To the east of the route is Mojave Air & Space Port, home to the National Test Pilot School and SpaceShipOne, the first privately funded human spaceflight,[12] as well as a vast airplane graveyard; all are visible from SR 14.[10]

The northern terminus of SR 14 near Inyokern

SR 58 was formerly routed concurrently with SR 14 through Mojave, before it was rerouted onto a bypass running north and east of the town.[10]

The character of the highway changes as it leaves California City with the last interchange located at California City Boulevard. Now a divided highway with at-grade intersections, departs the corridor of the rail main, to follow the crest of the forming Sierra Nevada mountains. The route continues to follow a branch line of the Union Pacific Railroad used as a connector for the Trona Railway. The main line of the railroad proceeds towards the Central Valley via Tehachapi Pass. Though SR 14 heads away from the pass, the highway has views of the mountains and the Tehachapi Pass Wind Farm. The scenery also changes, as the highway departs the Mojave Desert and crosses Red Rock Canyon State Park. Traffic counts drop dramatically as the highway becomes more rural, with an AADT of 3,200 vehicles at the northern terminus.[7] SR 14 continues north toward US 395 in Inyokern, much of its routing as an expressway. Towards its northern terminus, SR 14 runs briefly concurrently with SR 178. At its northern terminus, SR 14 merges with US 395 as it turns into an expressway heading north to Bishop. As US 395 the route continues to follow the crest of the Sierra Nevada, serving Owens Valley, Mammoth Mountain, Yosemite National Park and Mono Lake.[10]

Looking south at the corner of Sierra Highway and Lancaster Boulevard in Lancaster c. 1918

The first road to use the general alignment of modern SR 14 was called the El Camino Sierra, or Sierra Highway, which extended from Los Angeles to Lake Tahoe. A dirt road was completed in the 1910s from what had been a pack trail. The Los Angeles Times declared El Camino Sierra complete in 1931, when the portion from Mojave to the Owens Valley, along modern US 395, was paved.[13]

During the late 19th century, the corridor of modern SR 14 was also in use by the Southern Pacific Railroad. South of Mojave was used for a main line, the corridor north of Mojave follows a branch line. The main line connected Los Angeles with the Central Valley, via Soledad Pass and Tehachapi Pass. While significantly longer than the more direct Ridge Route (east of modern I-5), Tehachapi Pass is lower than Tejon Pass along the Ridge Route, with a longer, less steep grade on the descent into the Central Valley.[10] While the Tehachapi Pass portion of this line has remained the same, over time another route was built from Mojave, across the Antelope Valley towards Cajon Pass to cross the San Gabriel Mountains, there merging with another main rail trunk to Los Angeles. The Cajon Pass fork remains the primary freight rail line to connect southern and northern California in use today, now owned and operated by the Union Pacific Railroad.[14] The fork paralleling SR 14 and crossing at Soledad Pass is still a contiguous line, but not used for through freight traffic as a significant portion was sold to the predecessors of the Southern California Regional Rail Authority to become the Antelope Valley Line of the Metrolink commuter rail service. The branch north of Mojave was built when the Southern Pacific acquired the unfinished Carson and Colorado Railroad in 1900.[15] The Southern Pacific built a standard gauge connector to the narrow gauge Carson and Colorado line from their main at Mojave. Although plans were to eventually convert this acquired line to standard gauge, most of the line was abandoned before the conversion was complete. The southern portion of this line is still active and connects to the Trona Railway.[10][16]

The Midland Trail was one of the first organized coast-to-coast trails in the United States.[17] In the trail's infancy, its routing changed numerous times. By 1925, the Midland Trail was established along what is modern State Route 168, joining El Camino Sierra in Big Pine.[18] Other named trails that eventually followed this route included the Theodore Roosevelt highway,[18] and Grand Army of the Republic Highway.[19] Parts of modern SR 14 continue to be signed with these names,[6] and north of Los Angeles County is still officially designated "El Camino Sierra / Midland Trail" as well as the aforementioned "Aerospace Highway".[6]

US 6 was extended from Greeley, Colorado, to Long Beach, California, on June 21, 1937.[19] Most of this extension used the Midland Trail, although the route entered California from Nevada slightly north of the previous route of the Midland Trail, instead passing through Bishop. While being designated US 6, parts of modern SR 14 were upgraded to freeway standards.

As part of the 1964 state highway renumbering, US 6 was truncated at Bishop. The portion of US 6 from Inyokern to Los Angeles was designated SR 14. Previously, the SR 14 designation was used for Artesia Boulevard and Lincoln Avenue, in the Los Angeles area, a portion of modern SR 91.[20]

Between 1963 and 1975, significant portions of US 6/SR 14 were moved to a freeway alignment. The former routing south of Mojave (and the current routing to the north) is still known as Sierra Highway. The first freeway section, from just east of Solemint Junction to Red Rover Mine Road, was completed in 1963. Further portions in the intercanyon areas of Acton to Soledad Pass were completed by 1965. By 1966, the freeway was complete as far north as Avenue P-8 (now Technology Drive) in Palmdale. The freeway was completed to Mojave by 1972.[21]

The Newhall Pass interchange, where I-5, Sierra Highway, Foothill Boulevard, San Fernando Road and the southern terminus of SR 14 meet, has been the site of a number of catastrophic incidents. The interchange has partially collapsed twice due to earthquakes: the 1971 Sylmar earthquake and the 1994 Northridge earthquake. As a result of the 1994 collapse, this interchange was renamed the "Clarence Wayne Dean Memorial Interchange", honoring a Los Angeles Police Department motorcycle officer killed when he was unable to stop in time and drove off the collapsed flyover ramp from SR 14 south to I-5 south.[22] After both earthquakes, the collapsed portions were rebuilt and surviving portions reinforced.[23]

In 2007, two tractor-trailer trucks collided in a tunnel along the truck lanes for southbound I-5 at the interchange. A resulting fire started, soon encompassing the entire tunnel along with 30 other trucks and one passenger vehicle that were in the tunnel at the time. The truck tunnel was closed for several days for structural damage inspections and repairs.[24]

Route 14 inside Red Rock Canyon

SR 14 is an unfinished route, as the definition in the California Streets and Highways Code states that the route begins at SR 1 (Pacific Coast Highway), near Sunset Boulevard in the Pacific Palisades area of Los Angeles.[25] Between the constructed end and legislative end of SR 14 are the community of Reseda and Topanga State Park. There is no paved road that directly connects these two points, with SR 27 or I-405 being the nearest through roads in this area.[26]

The interchange with Sierra Highway at Via Princessa in Santa Clarita has an unusual design, with long flyover ramps for the connections. This is the result of a freeway revolt by the residents of Santa Clarita that canceled plans for a freeway extension of SR 126.[27] While the Via Princessa alignment of SR 126 was canceled, the city of Santa Clarita constructed the Cross Valley Connector[28] (CVC) to connect SR 126 directly to SR 14 via Newhall Ranch Road and Golden Valley Road. The final CVC section, the bridge over the Santa Clara River, was opened on March 27, 2010.[29]