At one point it was also planned to be just north of SFO. Have you ever taken I-380 east instead of one of the exits to 101N/S? There's a huge multi-lane road that dwindles to basically an airport access road exit.
Oh man, thanks for those links. TIL. A causeway or something that extends off of Alameda? It's wild to think about what that would have done to the area.
It would have probably been the continuation of I-980 had that bridge been built: https://en.wikipedia.org/wiki/Interstate_980#History
At one point it was also planned to be just north of SFO. Have you ever taken I-380 east instead of one of the exits to 101N/S? There's a huge multi-lane road that dwindles to basically an airport access road exit.