Interstate 380 California


Interstate 380 is a busy connector linking I-280 at San Bruno with U.S. 101 (Bayshore Freeway) at South San Francisco and San Francisco International Airport (SFO). I-380 constitutes a six lane freeway with auxiliary lanes added between entrance and exit ramps.

Ramps at San Francisco International Airport (SFO) were upgraded in the early 2000s as part of an expansion project that included a new terminal. An extension of the Bay Area Rapid Transit (BART) system, which commingles with the I-380 ramps, enhanced access to the airport.


I-380 was established by the December 1968 Federal Aid Highway Act. It was constructed by the early 1970s to replace then-California 186. Designated the Portola Freeway, it was also named the Quentin Kopp Freeway in the 1990s.

Plans previously called for extending Interstate 380 west from I-280 to California 1 at Pacifica. Heavily disputed due to environmental, terrain, and traffic impact issues, the roadway remains unbuilt. Provisions were however made at the interchange joining I-280 and I-380 and exit numbers start at five, referencing the unconstructed alignment from Pacifica.

Throughout the latter half of the 20th century, studies also called for additional crossings of San Francisco Bay. One of the corridors considered was a bridge system linking Interstate 380 on the San Francisco Peninsula with Interstate 238 at the East Bay. The crossing was envisioned to span the bay near its widest point. Several obstacles, including funding and mitigating for environmental concerns, prevented the proposed route from moving forward. The I-380 proposal was separate from the "Southern Crossing", a cross bay route considered from San Francisco to Alameda.

Highway Guides

Western Terminus - Interstate 280 - San Bruno, California
Perspective from Interstate 380 west
Westbound Interstate 380 approaches the directional T interchange with I-280 (Father Junipero Serra Freeway). The forthcoming exchange includes provisions for the planned extension of I-380 west to SR 1. A separate proposal considered extending I-380 west to nearby SR 35 (Skyline Drive). Photo taken 03/26/16.
The Interstate 380 mainline defaults motorists onto I-280 north with three lanes. Left Exit 5B takes drivers south toward San Jose. Photo taken 07/11/18.
Traffic separates into the flyovers for Interstate 280 as I-380 ends. Photo taken 03/26/16.
Historic Perspective from Interstate 380 west
Button copy signs for Interstate 280 were replaced by 2008 to display Exits 5B/A. Photo taken 11/26/04.
The three lane off-ramp for I-280 passed over Cherry Avenue and separated with three lanes north to San Francisco and two south to San Jose. Photo taken 11/26/04.
Perspective from Interstate 280 south
Southbound Interstate 280 approaches Exit 43A for I-380 east to San Francisco International Airport (SFO). Exit 43B, a distributor roadway connecting with Sneath Lane and San Bruno Avenue, would have served the western extension of I-380 had it had been constructed. Photo taken 07/11/18.
An auxiliary lane accompanies I-280 south from Avalon Drive to the back to back ramps for Sneath Lane (Exit 43B) and Interstate 380 (Exit 43A) east. Photo taken 07/11/18.
Interstate 380 leads directly to San Francisco International Airport (SFO) from I-280. I-380 is also the lone freeway linking I-280 with U.S. 101 between San Francisco and San Mateo. Photo taken 07/11/18.
Taking Exit 43A, a two-lane ramp carries drivers from I-280 south to I-380 east below an abandoned overpass built for the western extension. Photo taken 11/26/04.
Historic perspective from Interstate 280 south
Replaced button copy sign for I-380 and U.S. 101 at the Avalon Drive under crossing. Photo taken 11/26/04.
Ramps departed I-280 south for Sneath Lane, San Bruno Avenue and Interstate 380 east. Photo taken 11/26/04.
Eastern Terminus - U.S. 101 - South San Francisco, California
Perspective from Interstate 380 east
Leading away from I-280, Exit 5 quickly departs Interstate 380 east for California 82 (El Camino Real) in San Bruno. An unused roadway remains in place between the I-380 roadways from the unbuilt extension. Travelers otherwise advance toward the cloverstack interchange with U.S. 101. Photo taken 07/11/18.
Interstate 380 advances east from El Camino Real toward the cloverstack interchange (Exit 6) with U.S. 101. Photo taken 07/11/18.
The I-380 mainline defaults onto ramps for both North Access Road and South Airport Boulevard. The ensuing exit departs for both U.S. 101 south and the passenger terminal at SFO Airport. Photo taken 07/11/18.
A two-lane flyover (Exit 6B) follows from Interstate 380 east for northbound U.S. 101 through South San Francisco. Photo taken 07/11/18.
A viaduct extends east along Interstate 380 over three streets and a railroad corridor to North Access Road (Exit 7) and South Airport Boulevard. Photo taken 07/11/18.
The signalized end of the freeway connects I-380 with North Access Road to a variety of aviation-oriented businesses along the northern periphery of the airport property. Photo taken 07/11/18.
Historic perspective from Interstate 380 east
Button copy signs previously posted at the six-ramp parclo interchange (Exit 5) with SR 82 (El Camino Real). Photo taken 11/26/04.
Photo taken 11/26/04.
Following Exit 6A to the separation for U.S. 101 south and the passenger terminal flyover ramps. Photo taken 11/26/04.
Perspective from U.S. 101 south
U.S. 101 travels through an industrial area of South San Francisco into the cloverstack interchange (Exit 423) with Interstate 380 west and the ramps to San Francisco International Airport (SFO). Photo taken by Joel Windmiller (04/07/02).
Perspective from San Francisco International Airport Access Road west
Departing from the passenger terminal of San Francisco International Airport, these signs direct motorists to the freeway system. Photo taken 07/23/16.
A direct flyover links the SFO Airport terminal area with Interstate 380 west. Photo taken 07/23/16.
I-380 offers a quick route between SFO Airport and Interstate 280 for the western half of San Francisco. I-280, in conjunction with SR 1 (19th Avenue), allows travelers bound for Marin County and points north to use the Golden Gate Bridge without having to drive through the city on Van Ness Avenue (U.S. 101). Photo taken 11/29/04.
Airport Access Road separates into ramps for U.S. 101 (Bayshore Freeway) and the flyover for I-380 to San Bruno, Pacifica and Daly City. Photo taken 11/29/04.
Ramps from both Airport Access Roads combine and turn north to run parallel with U.S. 101 (Bayshore Freeway) north directly to Interstate 380 west. Photo taken 11/29/04.
Photo taken 07/23/16.
Perspective from U.S. 101 north
U.S. 101 (Bayshore Freeway) runs along the west side of San Francisco International Airport (SFO) as it travels between San Jose and San Francisco. Travelers continue 1.25 miles beyond the passenger terminal exit to Exit 423B for Interstate 380 west. Photo taken 03/26/16.
U.S. 101 passes under the multi level interchange with SFO Airport one mile ahead of I-380 west to Interstate 280 (Junipero Serra Freeway). Photo taken 03/26/16.
A two lane flyover parallels the northbound lanes of U.S. 101 from the passenger terminal of SFO Airport directly to Interstate 380 west. Succeeding ramps depart from the Bayshore Freeway mainline for San Bruno Avenue (Exit 423A) to various car rental and air cargo facilities and I-380 west to San Bruno. Photo taken 03/26/16.
A two-lane off-ramp departs just to the north of the San Bruno Avenue exit for Interstate 380 west. I-380 connects U.S. 101 with parallel California 82 (El Camino Real) in addition to I-280. Photo taken 03/26/16.
San Bruno Avenue spans U.S. 101 (Bayshore Freeway) as Exit 423B parts ways for Interstate 380 west. The adjacent flyover lowers and separates into slip ramps for both I-380 west and the U.S. 101 c/d roadway for San Bruno Avenue. Photo taken 03/26/16.
Perspectives from Airport Boulevard
Airport Boulevard stems north from the intersection of San Bruno Avenue and McDonnell Road and parallels U.S. 101 to Gateway Boulevard at San Mateo Avenue. The arterial route connects the car rental facilities of SFO Airport with the westbound beginning of I-380 as well. Photo taken 11/26/04.
A direct ramp joins Airport Boulevard with I-380 west as flyovers connecting North Access Road with U.S. 101 pass overhead. An access road to the east provides links with the U.S. 101 ramps from adjacent North Access Road. Photo taken 11/26/04.
Airport Boulevard south at the freeway entrance for Interstate 380 west and U.S. 101 north. Photo taken 03/26/16.
The on-ramp from Airport Boulevard provides access to both Interstate 380 west and U.S. 101 north. Photo taken 03/26/16.
Following the access road east from Airport Boulevard, motorists approach a parking garage and the intersection with North Access Road and Interstate 380 west. Photo taken 11/26/04.
North Access Road west transitions directly onto Interstate 380 west as flyovers depart for U.S. 101 (Bayshore Freeway). North Access Road east encircles SFO Airport to air cargo facilities. Photo taken 11/26/04.
Perspective from North Access Road west
North Access Road west transitions to Interstate 380 beyond the traffic signal with the Airport Boulevard connector road. Photo taken 07/11/18.
Single lane flyovers follow for I-380 to San Bruno, U.S. 101 south to San Jose and U.S. 101 north to San Francisco. Photo taken 07/11/18.

Page updated March 11, 2019.