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.
East End – South San Francisco, CA
West End – San Bruno, CA
Mileage – 3.30
Cities – San Bruno, South San Francisco
- Junctions –
Source: December 31, 2018 Interstate Route Log and Finders List
I-380 Annual Average Daily Traffic (AADT)
|Location||Vehicles per day|
|I-280 to Exit 5||143,900|
|Exits 5 to 6||169,100|
|US 101 to S Airport Rd||23,700|
Construction of Interstate 380 displaced the full cloverleaf interchange between U.S. 101 (Bayshore Freeway) and San Bruno Avenue. A portion of the original footprint remains visible on the west side of the junction today.
East End / N Access Road – South San Francisco, California
East at / North Access Road
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)
San Francisco International Airport Access Road west at
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 to San Bruno, Pacifica and Daly City. 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). Photos taken 11/29/04.
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.
Airport Boulevard / North Access Road at
West End – San Bruno, California
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.
Page updated March 11, 2019.