Skip to main content

Interstate 380

This past weekend I drove over twenty Californian highways with a good chunk of them being around the San Francisco Bay Area.   The first highway I attempted was Interstate 380 from San Francisco International Airport west to I-280.


I-380 is an approximately 1.7 mile freeway connecting from US 101 at San Francisco International Airport west to I-280.  The entire routing of I-380 is within San Mateo County and despite it's small size was conceived as a much larger route.

According to CAhighways.org the path of I-380 was first conceived as Legislative Route Number 229 in 1947 between US 101 Bypass west to US 101 in San Bruno.

CAhighways.org on LRN 229

LRN 229 was extended to CA 1 Pacifica in 1959 by the Legislature.  While LRN 229 in it's original form was too small display on State Highway Maps it does appear in full scope by the 1960 addition.

1960 State Highway Map

During the 1964 State Highway renumbering LRN 229 was reassigned as LRN 186 which is reflective on the State Highway Map of the same year.

1964 State Highway Map

According to CAhighways.org the path of LRN 186 was authorized to be built as part of the Interstate system in 1968.  By 1969 the route of I-380 was defined by the Legislature and it's implied path appears on the 1970 State Highway Map .

1970 State Highway Map 

I-380 is shown as mostly complete between US 101 and I-280 on the 1975 State Highway Map.  There appears to be a small gap over the rails between CA 82 (former US 101) and US 101 on the Bayshore Freeway (former US 101 Bypass).

1975 State Highway Map

On the 1977 State Highway Map I-380 is shown fully completed between I-280 and US 101.

1977 State Highway Map

The extension of I-380 west to CA 1 in Pacifica would be cancelled by 1979 according to CAhighways.org.

CAhighways.org on Interstate 380

Interestingly I-380 has been the subject of several proposals for a new bridge across San Francisco Bay with the latest popping up in 2017.  Most of the modern proposals would have the new crossing connecting with I-238 which would in theory remove the Interstate numbering violation.  CAhighways.org summaries the I-380 extension proposals on the above link.

My approach to I-380 was from US 101 northbound at San Francisco International Airport.






As I approached the westbound ramp for I-380 there was a small but strong storm overhead.  While my photos didn't turn out all that great given the strong rains I was able to get some "acceptable" enough samples to convey the route.  As I-380 ascends over US 101 it enters the City of San Bruno.




I-380 westbound meets CA 82 approximately in the middle of it's routing.  CA 82 is the historic route of the El Camino Real and original alignment of US 101 before the Bayshore Freeway was built.



I-380 westbound terminates at I-280.  Traffic is given the option of heading both northbound and southbound on I-280.



Comments

Unknown said…
The next time you are in the area, you might want to approach I-380 from southbound 280. As you follow that ramp you will see an "overpass to nowhere" which apparently was meant to be the first piece of the planned westward extension over the hills to Pacifica.
I noticed that the exits on I-380 are numbered 5 for CA-82, but then 5A and 5B for I-280. Do you have any idea for the numbering discrepancy? Shouldn't the CA-82 exit have been numbered 5C, or I-280 4A and 4B?

Popular posts from this blog

Sunshine Bridge (Donaldsonville, LA)

Located about halfway between Baton Rouge and New Orleans in southern Louisiana, the Sunshine Bridge spans the lower Mississippi River near the city of Donaldsonville as part of the longer Louisiana Highway 70 corridor, which connects Interstate 10 and Airline Highway (US 61) with US 90 in Morgan City. In the years following World War II, the only bridges across the lower Mississippi River in Louisiana were located in the area of the state’s two largest cities – Baton Rouge and New Orleans. Postwar agricultural and industrial development along the river in this region led to the planning of a series of infrastructure projects in southern Louisiana that were aimed at spurring this development and modernization of the Delta region. One of these projects was known as the Acadian Thruway and was developed in the 1950s as a toll road intended to connect greater New Orleans with Lafayette and points west while providing a high-speed bypass of the Baton Rouge metro area. The Thruway, which

Old River Lock & Control Structure (Lettsworth, LA)

  The Old River Control Structure (ORCS) and its connecting satellite facilities combine to form one of the most impressive flood control complexes in North America. Located along the west bank of the Mississippi River near the confluence with the Red River and Atchafalaya River nearby, this structure system was fundamentally made possible by the Flood Control Act of 1928 that was passed by the United States Congress in the aftermath of the Great Mississippi River Flood of 1927 however a second, less obvious motivation influenced the construction here. The Mississippi River’s channel has gradually elongated and meandered in the area over the centuries, creating new oxbows and sandbars that made navigation of the river challenging and time-consuming through the steamboat era of the 1800s. This treacherous area of the river known as “Turnbull’s Bend” was where the mouth of the Red River was located that the upriver end of the bend and the Atchafalaya River, then effectively an outflow

Huey P. Long Bridge (Baton Rouge, LA)

The decade of the 1930s brought unprecedented growth and development to Louisiana’s transportation infrastructure as the cities of New Orleans and Baton Rouge cemented their place as leading urban centers on the Gulf Coast. In the immediate aftermath of the success garnered by the construction of the massive bridge on the Mississippi River near New Orleans in 1935, planning and construction commenced on the state’s second bridge over the great river. This new bridge, located on the north side of Baton Rouge, was to be similar in design and form to its downriver predecessor. Completed in 1940 as the second bridge across the Mississippi River in Louisiana and the first to be built in the Baton Rouge area, this bridge is one of two bridges on the Mississippi named for Huey P. Long, a Louisiana politician who served as the 40th Governor of the State from 1928 to 1932, then as U.S. Senator from 1932 until his death by assassination at the state capitol in Baton Rouge on September 10, 1935