James Lick Skyway

[Voyager]

Now that this thing is being rebulit, I'm wondering if Caltrans is actually going to let us know where I-80 ends, and where US-101 begins on the skyway. For years I know that many people have been wondering!

[agentsteel53]

follow the I-80 postmiles down to zero? 

[John]

Postmiles say the west end of the Bay Bridge, but signage indicates it begins at US-101. Of course, every DOT in the world seems to hate end signs, so we probably won't have any luck on the new James Lick.

[Voyager]

Exactly, and knowing Caltrans, we'll never be sure.

[rebel049]

According to an FHWA map at http://www.fhwa.dot.gov/planning/nhs/maps/ca_north/sanfrancisco_ca.pdf dated April 2004, Route 80 is a Non-Interstate STRAHNET Route from Route 101 to just east of the old Route 480 and then then classified as part of the Eisenhower Interstate System from that point eastward on.

[John]

Plus there is a state route 80 sign. Maybe its like the Chicago Skyway, although the skyway actually is part of the IHS.

[TheStranger]

Plus there is a state route 80 sign. Maybe its like the Chicago Skyway, although the skyway actually is part of the IHS.

Yet the entirety of the "non-interstate" I-80 between old 480 and 101 has always been signed as an interstate.

I've always felt that the truncation of "interstate" status at 480 was more of a mistake from those writing the route definition in the late 60s (when 280 was rerouted from the 19th Avenue/Junipero Serra corridor to then-existing Routes 82 and 87) than the intended situation today; 80 originally was slated to run west to Route 1/originally planned I-280 in Golden Gate Park along the Central Freeway and then on the never-built Western Freeway down Fell Street.  So the truncation seems to have been intended to delete the Western Freeway routing and nothing more than that, though the way it was written results in today's technicality.  (Does that mean that the existing segment of the Central Freeway was built as I-80/US 101?  That, I've never seen an answer to, though the interchange design makes me wonder.)

The Skyway itself was not constructed as I-80 except for the segment between 10th Street and US 101; part of the segment to the bridge was originally built as US 40/50 in the 1930s/1940s and retained that signage in I-80's earliest years.  Maybe that's why it was removed from the Interstate system, due to having been built before it?