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Battle of the blueprints: Should I-280 stay or should it go?

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As city planners consider a Caltrain extension in Mission Bay, conflicting plans have emerged about whether segment of I-280 must come down. (Jessica Christian/S.F. Examiner)

Some San Francisco residents are roaring over a study to explore tearing down a portion Interstate Highway 280 in Mission Bay, which could clear the way for a Caltrain extension downtown.

But two sets of blueprints obtained by the San Francisco Examiner paint contrasting futures of I-280, including an effort to put the brakes on the proposal decades ago.

One set of blueprints, drawn in 1969, planners say shows evidence that to build a new Caltrain extension, I-280 must come down — no questions asked.

The other set of plans, two decades old, purportedly shows a road not taken — how the Caltrain extension could be built without the need to tear down I-280.

Meanwhile, the latter idea is gaining support. After a packed public meeting last month when local residents of Potrero Hill and The City’s southeast booed and hissed over the proposal, political heavyweight John Burton, the state’s democratic party chair and a former congressman, joined a chorus of voices denouncing the plan.

“Well, I think it’s stupid,” he told the Examiner of the possibility of tearing down I-280. “It’ll clog up Potrero.”

He’s not alone. Former Mayor Art Agnos previously told the Examiner he would personally launch a campaign against the I-280 teardown if it were pursued.

Planners are now preparing for another meeting on March 30 to discuss the possibility of tearing down the freeway, which they argue will “open up” Mission Bay to the community.

Plan 1: Narrow Freeway Must Come Down

Blueprints of I-280 drawn in the 1960s by the Department of Public Works show one glaring issue, planners argue:

I-280 is too narrow to bore a tunnel underneath.

The blueprints show I-280’s pylons are 24 feet apart. That’s smaller than any train tunnels that could be dug up beneath the freeway, wrote Susan Gygi, in an analysis sent to the Mayor’s Office in February.

Even though the pylons are 24-feet on centerline, “inside spacing — or the width between the edge of a piling to another piling — is less than that,” Gygi wrote in an email to Gillian Gillett, the mayor’s transportation director.

“Big Alma,” the main boring machine used in 2014 to dig the hole for the Central Subway in Chinatown, has a diameter of 22-feet, Gygi wrote. But a single tunnel bore is at least 28 feet in diameter — too wide to fit.

Above, “Big Alma” tweets a photo of its tunnel from the official Big Alma Twitter account.

And forget tunneling two bores around the pilings, she wrote. If that were tried, “you wouldn’t be able to ‘bring them together’ in the space that you have before entering the downtown extension,” Gygi wrote.

Only if I-280’s pylons come down, she argued, would tunneling be possible.

Plan 2: Tunnel a Walkway

When told I-280 must come down, a retired Bay Area engineer had essentially one reply: Nope.

Gerald Cauthen is a retired engineer from consultants Parsons Brinckerhoff Quade & Douglas, Inc., based in San Francisco. While most retirees keep knick knacks from the office, like a favorite paperweight, Cauthen kept blueprints.

Lots of blueprints.

Among them are a set of drawings labeled with the Muni “worm” logo, titled “Phase 1 Design Conceptual Engineering Drawing,” which was last redrawn Nov. 5, 1993.

Cauthen says these plans show another solution to extending Caltrain downtown.

The plans show Caltrain tracks to the Downtown Extension depressed only five feet below the surface, instead of tunneling underground.

To join Mission Bay with the rest of The City, the blueprints feature a construction nowhere else in San Francisco — an underground roadway, and accompanying pedestrian passage.

It’s far better, Cauthen said, than tearing down I-280 and turning the freeway into a boulevard.

“Putting four lanes of northbound freeway traffic headed to downtown San Francisco onto Seventh Street would cause a mess,” he said, “To avoid this, at least half the traffic would have to be diverted farther south.”

But there aren’t any viable alternatives to reroute those cars, he said, which would lead to future traffic snarls in Mission Bay. Mariposa, Third and Cesar Chavez streets as well as other roadways may all encounter traffic burdens under the plan, he alleges.


Blueprints #1: Shows the narrowness of I-280, which planners argue mean the freeway must come down to tunnel. (Click here to view).

Blueprints #2: Shows unused plans for underground roadway/walkway. (Click here to view).

Ed Reiskin, director of transportation at the San Francisco Municipal Transportation Agency, said that plan doesn’t pan out.

“Forcing us to create depressed canyons to connect Mission Bay to the rest of The City would be problematic from a land use and transportation standpoint,” Reiskin said on KALW radio, in mid-March.

Cauthen said, as a counterpoint, “We think you could build the downtown [Caltrain] extension and keep the freeway where it is.”

The mayor’s office and city planners, however, have other ideas.

Looking to the Future

The mayor’s transportation director, Gillian Gillett, wrote to Caltrain in 2013 arguing a need to raze I-280 and relocate the Caltrain railyard to make way for more office and housing development in Mission Bay.

When asked if tearing down I-280 is to benefit development, Gygi told the Save Muni group that failing to plan for more offices and more housing would be inconsistent with projections for San Francisco’s inevitable population boom.

Local group Plan Bay Area gives numbers of anticipated growth to each of the regions, she said, and to San Francisco it anticipated “200,000 jobs and 100,000 housing units by 2040.”

“We’re trending almost five years faster than that,” she warned.

Those new people will have to live and work somewhere. The question is, whether they’ll have a view of I-280 in their backyard.

Click here or scroll down to comment

  • sojourner_7

    Face it, those who want to tear down 280 are far more interested in the real estate grab than any transit issues. MTC. The Transbay Terminal needs something they can sell bonds from, so it’s rob Peter (280 land) to pay Paul.

  • c.g.


  • BFlatlander

    Its a SCAM

  • bruce

    Keep 280 you idiots 101 is already congested enough as it is.

  • CitygalSF

    Tearing down 280 has about as much to do with transportation as the Stockton Subway to Nowhere. It’s *always* about development. Thank goodness for the foresight and perserverence of Mr. Cauthen.

  • OrdinaryJoe

    The proposed City planning idea of tearing down the 280 extension and loading everyone on to 101 N and S is someone’s wet dream.

    Traffic will be overloaded on 101 North and the exits at Bayshore, Cesar
    Chavez, Silver Ave, Vermont, etc. Lot of people use 280 to get to their homes on Potereo Hill, Bernal Heights, etc. Not to mention just getting into Downtown, AT&T Park, the Embaradero, the Warriors new stadium, etc. Now with all the new businesses (plus the new UCSF Benioff Children’s Hospital) and increased housing in the Mission Bay area, it gets tougher.

  • Liz Brisson

    It would be helpful for this article to also explain the new alignments for the Downtown Extension of Caltran (DTX) that were recently studied by SF Planning and their consultant team. My understanding is that the conclusion of these studies (that also reflect changes in technology that engineering plans done decades ago would not) is that you could produce a better straighter bored DTX alignment that could allow I-280 to remain. I personally am a fan of tearing it down, but think it is important to justify it based on its own costs, benefits, and trade-offs, not as inextricably linked to DTX/high-speed rail. (speaking as an individual)

  • MustRunFaster

    The Central Subway’s Chinatown terminus will be in the middle of the one of the densest neighborhoods in North America, a neighborhood where over 80% of the residents don’t own a car. How can you possibly call it a “Subway to Nowhere” in the face of those facts? It’s amazing how invisible Chinese people are in this city sometimes. I recently spoke to a man who had owned a restaurant for almost a decade just a few minutes walk from Chinatown and he literally told me “Oh, I didn’t know anybody lived in Chinatown.” SERIOUSLY??? People around here spend so much time in their cars that they’re oblivious to their own city.

  • Bryan Culbertson

    How about a compromise: Tear down 280, replace it with underground rail and highway?

  • Mike Murphy

    No luxury condo owner wants “a view of I-280 in their backyard”.

  • sebra leaves

    NO WAY!

  • Brian Stokle

    Nice idea but WAY to expensive.

  • wave9x

    Why is the mayor piggybacking this dumb Mission Bay initiative with the Caltrain downtown extension? The two are totally separate projects. Build the Caltrain downtown extension NOW, deal with this Mission Bay pipe dream at your leisure.

  • CitygalSF

    I’m very aware that Chinese people live in Chinatown, and that they’re also the majority in my neighborhood, which connects to Chinatown via the MUNI 8 bus. Chinatown is also served by the 30, 45, 12, and 1 California lines, as well as being very walkable from BART, the Financial District etc. My point was not that Chinatown is “nowhere” but that the subway actually threatens current Chinatown residents, many of them low-income. The subway is not being built for them, but for the property owners who will cash in when Chinatown is re-zoned for higher-density development of luxury condos and offices, once it’s more convenient to get there from SOMA/Caltrain. It would also make much more sense to extend the subway all the way to North Beach/Fisherman’s Wharf.