Interstate 280 California
Often referred to as one of the most scenic urban freeways in America, Interstate 280 (Junipero Serra Freeway and Sinclair Freeway) comprises both an alternate and commuter route from San Francisco to San Jose. Bypassing the more industrial and crowded U.S. 101 (Bayshore Freeway), I-280 is eight lanes throughout. It follows the San Andreas fault line along the San Francisco peninsula.
Originally planned to connect with Interstate 80 near the San Francisco-Oakland Bay Bridge, I-280 ends just shy of the parent route. It used to extend as far as Third Street, but now concludes two blocks southwest of Oracle Park (home of the MLB San Francisco Giants), where it transitions onto King Street and ultimately the Embarcadero. California Department of Transportation (Caltrans) Postmiles extend along the I-280 ramps to Brannan Street instead of King Street.
Source: December 31, 2021 Interstate Route Log and Finders List
I-280 Annual Average Daily Traffic (AADT)
Source: Caltrans 2017 Traffic Volumes : Route 280-405
The south end of Interstate 280 defaulted traffic to U.S. 101 (Bayshore Freeway) until September 4, 1974, when I-680 was completed through San Jose.
Interstate 280 was added alongside SR 82 in San Francisco in 1965 and dropped along the freeway in 1968.
One of several routes cancelled during the San Francisco Freeway Revolt of the 1960s, Interstate 280 was originally proposed along a different course than where it ends today. As displayed on the 1964 Official California State Map, the section of today’s I-280 between SR 82 and I-80 was to be signed as a northern extension of SR 82 and SR 87.
I-280 was instead proposed to run northward along a corridor roughly paralleling SR 1 (19th Avenue). It was to follow Junipero Serra Boulevard, Portola Drive and Seventh Avenue, then skirt the eastern edge of Golden Gate Park, where it would have converged with a western extension of I-80. Continuing north, I-280 would have followed Park Presidio Boulevard into the Presidio. Interstate 280 would have ended at the southern end of the Golden Gate Bridge, where U.S. 101 would continue north to Marin County and Interstate 480 would turn east along the unconstructed Golden Gate Freeway and demolished Embarcadero Freeway to connect with I-80 at the San Francisco-Oakland Bay Bridge. This in effect would have created a belt freeway system for San Francisco.
However, between 1965 and 1968, San Francisco city government decided not to construct most of the planned freeway system. Short portions of SR 480 (Embarcadero Freeway) and U.S. 101 (Central Freeway) were built, but neither spur connected with another freeway beyond I-80. Since the proposed alignment of I-280 had yet to be constructed prior to the revolt, it was dropped from plans in its entirety. As a result, I-280 was rerouted onto the SR 82 corridor north to U.S. 101 and SR 87 from there to Interstate 80.
Interstate 280 was retracted two blocks west from 3rd Street and realigned onto King Street due in part from damage during the 1989 Loma Prieta Earthquake and the subsequent redevelopment in the vicinity of the San Francisco Giants ballpark. The elevated roadway previously ran directly along side the China Basin Water Channel from the Sixth Street ramps to a stub end at 3rd Street in South Beach.
North End Brannan and King Streets – San Francisco, California
North at 6th and King Streets
King Street extends from I-280 and 5th Street two blocks to Oracle Park (home of the San Francisco Giants) and South Beach. North from there, King Street transitions onto The Embarcadero toward the many bayside attractions that San Francisco has to offer, including Rincon Point, the Ferry Building, Pier 39, and Fisherman’s Wharf. 11/26/04
King Street – South at
King Street extends two blocks southwest from Oracle Park, home of the MLB San Francisco Giants to become Interstate 280 at the signalized intersection with 5th Street. 07/11/18
South End – San Jose, California
Entering the four level interchange with U.S. 101 north to Santa Clara and San Francisco and U.S. 101 south to Gilroy and Los Angeles.
Traffic departs U.S. 101 north for Exit 384 ahead of Story Road. Interstate 280 north arcs southwest toward Downtown San Jose, then north to Daly City and San Francisco. Interstate 680 travels north to Fremont, then angles northeast via Sunol Grade to Pleasanton / Dublin and onward to the San Ramon Valley. 03/25/16
U.S. 101 (Bayshore Freeway) meets Santa Clara Street / Alum Rock Road (SR 130) on the approach to I-280 north to Downtown San Jose and I-680 north to Fremont and Walnut Creek. SR 130 is a winding road to Mount Hamilton that was previously planned as a freeway from San Jose to the Central Valley. 11/29/04
Page updated November 5, 2020.