I noticed on the 1982 Caltrans highway map that I-380 had an eastward extension from US-101 - but not towards a proposed Southern Crossing like in the past. Instead, it crossed US-101, then turned south, running along today's McDonnell Road, then curving towards the terminals. In the 1986-1988-1990 maps there's something similar, but looks like it maybe included the full terminal access road from US-101.
(https://live.staticflickr.com/65535/54883823422_d6bcdb989c_b.jpg)
It's a dashed line, indicating that they had a definite route selected. CHPW was out of publication by this time, and my initial internet searching couldn't find anything. It appears (per cahighways.org) that the legislative definition never changed during this period - the route has ended at US-101 since 1970.
Anyone have any information or thoughts on this?
Shows as an adopted alignment also. That's strange, I've never noticed this on the 1982 map before.
Quote from: DTComposer on October 28, 2025, 12:45:12 PMI noticed on the 1982 Caltrans highway map that I-380 had an eastward extension from US-101 - but not towards a proposed Southern Crossing like in the past. Instead, it crossed US-101, then turned south, running along today's McDonnell Road, then curving towards the terminals. In the 1986-1988-1990 maps there's something similar, but looks like it maybe included the full terminal access road from US-101.
(https://live.staticflickr.com/65535/54883823422_d6bcdb989c_b.jpg)
It's a dashed line, indicating that they had a definite route selected. CHPW was out of publication by this time, and my initial internet searching couldn't find anything. It appears (per cahighways.org) that the legislative definition never changed during this period - the route has ended at US-101 since 1970.
Anyone have any information or thoughts on this?
Nice find. I'll put this on the pages as "Some maps show..." and steal your graphic (with credit, of course), while we search for more information.
Researching this a bit. https://historysmc.pastperfectonline.com/archive/FC23B0EA-39F7-475C-A5CA-669920879914 might provide some information:
QuoteScope & Content
04-San Mateo-186-X6.9-X7.6. Route 82 to Route 101, 1968-1974. Right of way acquisition documents for parcels of land in San Mateo County. This file shows undeveloped lands owned by the San Francisco International Airport in San Bruno needed for construction of the I-380 and Highway 101 Interchange.
Might be worth requesting. Thoughts? I don't know the process.
I did a bunch of searching as well, including going through the "Going Places", published by Caltrans around 1983 (and discovered that Caltrans withdrew from AASHTO membership 1980-1983). I couldn't find anything as well. My guess is that the answer lies in two potential places: (1) The I-380 files at the Caltrans history library; (2) the EIRs for the construction of I-380 in that area, as those often summarize the history. There might also be information in the city archives (or airport archives) for the involved cities, as they would also have the adoption records and public notices. Hunting that down requires physical presence in Northern California, which I don't have.
One additional thought: We might drop a note to the MTC. I seem to recall that one MTC person might be on this forum; perhaps they will respond.