Golden State Freeway

Interstate 5
Route information
Maintained by Caltrans
NHS	Entire route
Major junctions
South end	I-10 / SR 60 / US 101 in Los Angeles
Major intersections	SR 134 near Glendale SR 14 near Santa Clarita
North end	SR 99 in Lebec
Location
Country	United States
State	California
Highway system
Southern California freeways

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

Route description

I-5 and State Route 99 converge near the southernmost point of the San Joaquin Valley, approximately 30 miles (50 km) south of Bakersfield. At this point, the Golden State Freeway begins. It travels southward through the valley until sharply rising through Grapevine Canyon past Fort Tejon, Lebec, and the Frazier Park exit to cross Tejon Pass through the Tehachapi Mountains. Path 26 power lines, a southern extension of Path 15, follow the freeway across the pass, past Gorman, the Antelope Valley (Mojave Desert) exit, and on to Pyramid Lake. At one point along the treacherous route in Violin Canyon near Castaic, 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 (I-210) near Sylmar, the San Diego Freeway (I-405) in Mission Hills, and the Hollywood Freeway (US 101 & SR-170) in Sun Valley. Traveling through the cities of Burbank and Glendale, it closely follows the Los Angeles River as it skirts Griffith Park and other sections of the Hollywood Hills (the easternmost extensions of the Santa Monica Mountains). The Golden State ends at the East Los Angeles Interchange in Boyle Heights; I-5 continues thereafter as the Santa Ana Freeway.

While the former surface street portions of State Route 99 are often named the Golden State Highway or Golden State Avenue, Highway 99 itself is not called the Golden State Freeway.

Legal definition

The Golden State Freeway is Route 5 from the 5/10/60/101 Junction to Route 14, as named by the Metropolitan Transportation Engineering Board on February 28 1958. Note that the segment from State Route 14 to Highway 99 is still legally unofficial.

Earthquakes and the Golden State Freeway

The Golden State Freeway at rush hour in the San Fernando Valley

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 January 17, 1994 Northridge earthquake (and again had to be rebuilt).

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 (80 km) 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.

Exit list

Note: Except where prefixed with a letter, postmiles were measured in 1964, based on the alignment as it existed at that time, and do not necessarily reflect current mileage. The numbers reset at county lines; the start and end postmiles in each county are given in the county column.

Template:Golden State Freeway exit list

County	Location	Postmile	#	Destinations	Notes
Los Angeles (LA 16.88-R88.61)	Los Angeles	16.88		I-5 south (Santa Ana Freeway) – Santa Ana	Continuation beyond US 101
			R15.86		I-5 north (West Side Freeway) – San Francisco, Sacramento	Northbound exit and southbound entrance
			R15.86	221	SR 99 north – Bakersfield, Fresno	Northbound exit and southbound entrance