The northernmost stretch of Interstate 280 could be demolished and turned into an Octavia Boulevard-like parkway under options being considered by the California High-Speed Rail Authority.
The freeway currently ends around Fourth and King streets, near AT&T Park. But documents obtained by The San Francisco Examiner show it could be removed north of 22nd Street to accommodate high-speed rail, which is expected to travel through the Peninsula along Caltrain’s route.
City officials proposed removing the freeway to avoid tunneling several roads beneath the tracks of the proposed rail system.
High-speed rail officials wanted to underground 16th Street, Seventh Street and Mission Bay Drive because they said it would be dangerous for cars to cross the rail tracks. But officials with The City and UC San Francisco said that would cause problems for Muni, be unwelcoming to pedestrians and effectively cut off Mission Bay from the rest of San Francisco.
City officials would prefer to bury the lines, allowing the streets to remain at ground level. But engineering complications could require removal of the northern end of I-280 to make that possible.
Rail authority spokeswoman Rachel Wall said the agency is pursuing its original proposal, but also “reviewing the various alternatives for that area that the city of San Francisco has proposed and will continue to meet with them to discuss a design solution.”
Caltrain now runs beneath I-280 for about five blocks north of 18th Street. The rail authority wants to follow that path, burying a second set of tracks beneath Caltrain’s route. That would yield a total of four tracks, two buried and two at street level.
In a Sept. 28 letter, Leroy Saage, deputy director of the San Francisco County Transportation Authority, proposed five separate alternatives that avoided burying the streets. By December, those alternatives had been whittled to three, all of which would bury the tracks rather than the streets.
But Saage said there might not be enough room to fit four parallel tracks between the underground pilings that support I-280. In that case, he wrote, a length of I-280 “would be removed and reconstructed as a parkway from 18th Street north.”
In an interview, Saage said this “would not be trivial” and the idea is still conceptual.
“The proposal would really take down the last couple thousand feet of the freeway,” he said. “Right now, it’s a giant off-ramp. It has to end some place.”
Yet Mission Bay resident and UCSF professor Matt Springer was nonplussed by the idea.
“I’ve seen the Octavia experience and it can be a huge traffic jam both getting on and getting off,” Springer said. “That last leg of 280 serves a crucial purpose for the neighborhood.”
Impact on traffic difficult to estimate
During the average weekday commute, more than 23,000 vehicles travel the stretch of Interstate 280 that could be demolished to make way for high-speed rail, and residents and experts disagree about how that kind of traffic would affect nearby neighborhoods.
While 23,000 motorists are not a trivial matter, local streets should be able to handle them if they are redesigned properly, said Elizabeth Deakin, a professor of city and regional planning at UC Berkeley.
Deakin pointed to The Embarcadero as a highway successfully replaced by a boulevard. Tearing down I-280 could actually reduce traffic, she said, since commuters could convert to public transit with Caltrain improvements and the introduction of high-speed rail.
Mission Bay resident Corrine Woods said the community would rather turn I-280 into a boulevard than tunnel 16th Street beneath the rail line. But she said not enough information is available to evaluate traffic impacts.
Early analyses indicate that Third Street would have more traffic, but it’s too early to tell how much, said Leroy Saage, a deputy director of the San Francisco County Transportation Authority.
“Traffic is a bit like water,” Saage said. “When changes occur to it, the effects are not necessarily obvious at first.” -- Will Reisman
The California High-Speed Rail Authority has proposed one plan for trains to come through San Francisco, but The City opposes it. Here are the alternatives, from top layer to bottom layer of traffic.
California High-Speed Rail Authority proposal
- I-280 remains elevated
- Two sets of rails at ground level, as the Caltrain tracks are currently
- Buries a second set of rails deeper beneath the surface
- Tunnels 16th Street, Seventh Street and Mission Bay Drive
City’s preferred plan
- I-280 remains elevated
- All four rail lines buried between the pillars supporting I-280
- 16th Street, Seventh Street and Mission Bay Drive remain at street level
If there’s not enough space between the buried pillars supporting I-280 for the preferred option:
- I-280 is taken down, replaced by an Octavia Boulevard-like parkway at street level
- 16th Street, Seventh Street and Mission Bay Drive would cross the new parkway at street level
- All four rail lanes would be tunneled, with no underground pillars restricting their space
Sources: San Francisco County Transportation Authority, San Francisco Technical Working Group