Golden State Freeway

The Golden State Freeway is a north-south freeway running through Kern County and Los Angeles County, California. Originally built as U.S. Highway 99, it was re-signed as Interstate 5 in 1964.

The Route

I-5 and California State Highway 99 converge near the southernmost point of the San Joaquin Valley, approximately 30 miles south of Bakersfield. At this point, the Golden State Freeway begins. It travels southward through the valley until sharply rising to cross the Tejon Pass through the Tehachapi Mountains, continuing through Grapevine Canyon. At one point along the treacherous route, the separated northbound and southbound lanes actually invert, with the southbound lanes being to the east of the northbound ones. The freeway continues into the Santa Clarita Valley, and then crosses Newhall Pass through the Santa Susana Mountains to enter the San Fernando Valley, and in turn, Los Angeles. Several major freeways split from the Golden State Freeway within a few miles of this point: the Foothill Freeway near Sylmar, the San Diego Freeway in Mission Hills, and the Hollywood Freeway in Sun Valley. Traveling through the cities of Burbank and Glendale, it closely follows the Los Angeles River as it skirts the Hollywood Hills. It ends at the East Los Angeles Interchange in Boyle Heights; I-5 continues thereafter as the Santa Ana Freeway.

Earthquakes and the Golden State Freeway

On February 9, 1971, the Sylmar earthquake destroyed a portion of the Golden State Freeway, including its interchange (then under construction) with the Antelope Valley Freeway, between the Santa Clarita and San Fernando Valleys. It was soon rebuilt with greater seismic reinforcement, but nevertheless sustained heavy damage in the 1994 Northridge earthquake. However, the risk of earthquake damage to the freeway remains high, as the Grapevine route crosses the notorious San Andreas Fault. The risk along this route is such that the proposed high-speed rail corridor between Los Angeles and San Francisco, originally planned to be built within the Golden State Freeway's alignment, will instead veer east into the Antelope Valley, going through the cities of Palmdale and Lancaster before traversing the more seismically stable Tehachapi Pass on its way to Bakersfield. Despite adding over 50 miles of line to the railroad and 20 minutes to its travel time, the route change will save billions of dollars in construction costs, as Tehachapi Pass presents relatively few engineering challenges.

Communities

Communities along the Golden State Freeway include:

Connecting freeways

Freeways intersected by the Golden State Freeway include: