Interstate 380 (California)

Interstate 380 (California). Interstate 380 (I-380) is a short auxiliary Interstate Highway located entirely within San Mateo County on the San Francisco Peninsula. The highway serves as a critical east–west connector between two major north–south freeways, linking Interstate 280 in San Bruno with U.S. Route 101 (US 101) in South San Francisco. Its primary function is to facilitate traffic between San Francisco International Airport (SFO), the Silicon Valley, and the City and County of San Francisco.

Route description

Beginning at a complex cloverleaf interchange with Interstate 280 in San Bruno, Interstate 380 heads eastward, immediately passing near the Skyline College campus. The freeway traverses a corridor between the San Bruno Mountain state park lands and the residential and commercial areas of San Bruno and South San Francisco. It features a major interchange with El Camino Real (SR 82) before descending toward the San Francisco Bay shoreline. The highway terminates at a directional T interchange with US 101, just south of San Francisco International Airport. The route is entirely within the San Francisco Bay Area and is a key artery for airport-bound traffic and commercial freight moving between the Peninsula and the East Bay via the San Mateo–Hayward Bridge.

History

The corridor for Interstate 380 was originally planned as part of the Interstate Highway System's network to serve the growing traffic demands of San Francisco International Airport and the surrounding industrial areas of South San Francisco. Its designation was approved by the American Association of State Highway and Transportation Officials (AASHTO) in 1964. Construction faced challenges due to the terrain near San Bruno Mountain and the need to navigate existing urban development. The freeway was built in stages, with the final segment opening to traffic in 1976, providing a continuous link between Interstate 280 and US 101. The route has undergone subsequent improvements, including seismic retrofitting and modernization of its interchanges to meet current California Department of Transportation (Caltrans) standards.

Exit list

The entire route is in San Mateo County. {| class="wikitable" |- ! Location ! mi ! km ! Exit ! Destinations ! Notes |- | San Bruno | 0.00 | 0.00 | – | Interstate 280 – San Francisco, San Jose | Western terminus; cloverleaf interchange; I-280 exit 44B |- | rowspan="2" | South San Francisco | 1.15 | 1.85 | 1A | El Camino Real (SR 82) / San Bruno Avenue | Signed as exits 1A (east) and 1B (west) |- | 3.42 | 5.50 | 1B | US 101 – San Francisco, San Jose | Eastern terminus; T interchange; US 101 exit 421A |- ! colspan="6" | 1.000 mi = 1.609 km; 1.000 km = 0.621 mi |}

See also

* Interstate 280 * U.S. Route 101 in California * San Francisco International Airport * California State Route 82 * San Mateo County, California

Category:Interstate Highways in California Category:Transportation in San Mateo County, California