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Author Topic: New San Francisco Bay bridge should become an extension of Interstate 380.  (Read 7992 times)

DTComposer

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Re: New San Francisco Bay bridge should become an extension of Interstate 380.
« Reply #25 on: January 04, 2018, 03:09:02 PM »

I'm not going to pretend to know the exact traffic patterns, but it seems to me this crossing would only exacerbate existing problems: on one side I-880 in Hayward is already chronically congested, and on the other this bridge would put downtown SF-bound cars onto US-101 and I-280, both of which are also chronically congested.

I would think the point of a new crossing would be to relieve traffic coming from the north and east over the Bay Bridge into downtown (and vice-versa), so what about this: a new bridge splitting off I-80 around Albany, heading SSE about 5 miles to the northern tip of Treasure Island, then SE into downtown, paralleling the Bay Bridge. It would touch down around Broadway and go into a tunnel which would lead under the Financial District and to a series of underground parking garages, plus access to the BART stations at Embarcadero and Montgomery. Limited access to get out beyond, including an additional toll, to discourage thru traffic (i.e., heading to the south or west parts of the city or down the Peninsula).

Typing it out makes it look more ridiculous than it was in my head, but just spitballin' here.

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sparker

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Re: New San Francisco Bay bridge should become an extension of Interstate 380.
« Reply #26 on: January 04, 2018, 05:17:58 PM »

You certainly wouldn't want towers, but there's no need for towers across most of the bridge.  There's just a narrow ship channel in the middle and the rest of the bay is shallow.  Where it's marked as the tunnel, they could put a bridge just above the water level, supported by piers from underneath, just like the San Mateo Bridge.

I wonder if the SFO Airport would be friendly towards rebuilding the Airport BART station as a through running station, with the BART line continuing across the bridge or tunnel to the Castro Valley BART line.


Long-range plans extend BART down the peninsula to Santa Clara, where it is expected to meet the East Bay line coming down from Fremont (currently either U.C. or in planning stages) via San Jose.  Whether the airport will be directly on that line or functioning as a spur has yet to be determined; either way, taking tracks across the bay on a new facility will be tricky but probably at least as "doable" as the project as a whole.  Since the east end of this corridor looks like it's not too far south of Oakland International, there might be a push to "kill two birds with one stone", so to speak, by using such a BART line to physically connect the two airport facilities; currently Oakland is served by an elevated-train shuttle service from BART to the terminal.   

The BART mainline bypasses the SF Airport stop.  SF Airport is on a spur, and I was thinking the spur could be extended across the bay. 

You're correct about the spur aspect (there's an actual wye for trackage) of the SFO BART server; the main line extends south to the Millbrae Avenue station, where it terminates into storage tracks south of the station itself.  There seems to be easement along the Caltrain tracks as far as the Burlingame city line; the Caltrain/former SP line is pretty hemmed in by streets and housing south of there all the way past San Mateo.  If and when BART extends further south than Burlingame, it'll likely be in a tunnel under local streets.  But I do concur that if some sort of new bridge/tunnel has its landing near SFO, that might be a pathway for a new cross-bay BART line -- but given the layout of SFO, it probably won't be a direct extension of the spur (it would have to tunnel under runways, which might in itself be a non-starter) but rather employing another rail junction north of the main line -- probably right around the I-380 overpass; that would be optimal for a direct BART line into the tunnel section of that specific bridge proposal.  But I still maintain that the east end would be best utilized by serving Oakland Airport before joining the East Bay BART line through East Oakland. 
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mcarling

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Re: New San Francisco Bay bridge should become an extension of Interstate 380.
« Reply #27 on: January 27, 2018, 02:19:17 PM »

I won't attempt a comparative analysis against other ways to spend $12B, but this alignment makes sense to me.  It would alleviate congestion on the SF Bay Bridge, the San Mateo - Hayward Bridge, I880, and the section of US 101 between I380 and CA 92.  On the other hand, it would probably increase congestion on US 101 north of I380.
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US 97 should be 2x2 all the way from Yakima, WA to Klamath Falls, OR.

sparker

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Re: New San Francisco Bay bridge should become an extension of Interstate 380.
« Reply #28 on: January 27, 2018, 04:50:59 PM »

I won't attempt a comparative analysis against other ways to spend $12B, but this alignment makes sense to me.  It would alleviate congestion on the SF Bay Bridge, the San Mateo - Hayward Bridge, I880, and the section of US 101 between I380 and CA 92.  On the other hand, it would probably increase congestion on US 101 north of I380.

Since it would be a "relief route" for both the Bay/I-80 bridge and San Mateo/CA 92 bridge, it would likely increase congestion to some degree in both directions of US 101.  Also, the existing I-380 would likely experience additional congestion as traffic to the new bridge from I-280 would be added to the present load.
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bing101

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