South Bay leaders say the federal government just awarded it billions in funding.
The BART Silicon Valley Extension Program is the largest single public infrastructure project in Santa Clara County.
VTA says the project will bring in 75,000 jobs both in construction along with other long-term positions.
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The final phase is slated to bring four more stations to the South Bay including Downtown San Jose.
VTA will own the facilities and BART will operate and maintain it.
"People can get all around the region, know they have a reliable way to get there and have transportation," said Carolyn Gonot, VTA General Manager and CEO, "So you can live in the South Bay and work anywhere else in the region and you can get jobs to your jobs in Silicon Valley."
But the road to finishing the project has been bumpy, including delays and increasing costs all while BART expects to run out of $1.9 billion in federal and state assistance by April 2026.
But Friday, local leaders got a call from the Federal Transportation Administration, billions in funding is being granted to help finish the project.
"$5.1 billion," said Cindy Chavez, VTA Board Chair and Santa Clara County Supervisor. "This is the second largest investment that the federal government has made in any single transportation project in the country's history."
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VTA had to compete with other transit agencies across the country for the funding.
Local leaders say multiple factors played into what set the project apart, including the amount of tax dollars that helped fund it through voter approved measures.
"We taxed ourselves more locally than any other region to make this project possible," said San Jose Mayor Matt Mahan who's also on the VTA board. "So it's really the sacrifice and leadership of the residents of our community who have made this possible."
Still, there's a $700 million gap to close.
"We're going to have to work with our contractors to get really confirmed that what we're spending and how to shave that down to the best that we can to make sure we're living within our budget, it may mean rescoping parts of it," Chavez said.
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Work Chavez said has to happen fast since projects this large see costs escalate at least 5% every year.
"We're going to have to be ruthlessly disciplined about watching the taxpayers dollars every step of the way," she said.
The BART Silicon Valley Extension is expected to be completed by 2037.
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