SAN JOSE (CBS SF) -- The Santa Clara Valley Transportation Authority board of directors Thursday evening will vote on whether to certify an environmental impact report for Phase II of the BART Silicon Valley project that proposes construction of a single-bore tunnel and two station locations in downtown San Jose.
Directors will meet at 5:30 p.m. in the county Board of Supervisors chambers at 70 W. Hedding St. in San Jose and the BART extension is the first item on the agenda.
"VTA has explored ways to deliver the best, least disruptive project for the next six miles of BART Silicon Valley into downtown San Jose and Santa Clara," VTA spokeswoman Brandi Childress wrote in a blog post. "It is a project that will meet both the needs of the operator (BART) and expectations of community stakeholders and is prudent of taxpayers' dollars."
Phase I of the project was given the green light in March 2011 to extend BART tracks from the Warm Springs station in Fremont to a Milpitas station and then a Berryessa/North San Jose station.
An original environmental impact report for Phase II was released in December 2016. Public hearings were held in the beginning of 2017 near each proposed station and a final draft was completed after that and it was released to the public this past February.
The current staff recommendations for Phase II include extending the project 6 miles, and chooses the Downtown San Jose Station West and Diridon Station North options, as well as building the single-bore tunnel.
The options of San Jose Station West and Diridon Station North, rather than San Jose Station East and Diridon Station South, are being recommended by VTA staff because of proximity to other transportation, opportunities to work with existing buildings and because they would present less construction interference.
A single-bore tunnel is large in diameter and can house both sets of tracks at each station, Childress said. BART had initially preferred twin-bore tunnels that would be smaller in diameter and run side-by-side with one track per tunnel.
VTA staff pointed out in a letter to the board that a single-bore tunneling system would provide more flexibility for crossover tracks, give more options in storage for train cars, provide for reduced tunnel maintenance, and reduce impacts to traffic by not closing down Santa Clara Street and light-rail trackways on the road, among other positives.
A letter addressed to BART dated in late March and signed by California assemblymembers and senators like Ash Kalra, Jim Beall and Scott Wiener also stated opposition to the twin-bore tunnel proposal.
"Remembering the community disruption caused by BART's earlier twin-bore tunneling in San Francisco and the East Bay provides even more impetus for VTA to consider more advanced technology," the letter reads. "Fortunately today, such an alternative tunneling methodology exists."
BART general manager Grace Crunican wrote a letter last week indicating that BART staff would also recommend the single-bore option.
Following the VTA board's vote Thursday night, the BART board of directors will need to approve the project description at their scheduled April 26 meeting.
After that, a Record of Decision is anticipated from the Federal Transit Administration in June, which will allow the VTA to begin "engineering and pre-construction activities" for Phase II.
Phase I of the project, previously expected to be completed by the end of 2018, has hit "more challenges than anticipated," Childress wrote in a blog post in early March.
The aging infrastructure of BART, the control system changes at the Warm Springs station, a breakdown in communication between the agencies and a lack of expert staff resources have been listed as the main contributing factors to the possible delay.
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