SANTA CLARA (CBS SF) — BART trains are set to roll into Milpitas and East San Jose about a year from now. But from there, the transit system faces potential hurdles that could derail plans to bring it to Santa Clara.

U.S. Secretary of Transportation Anthony Foxx made a trip to the Bay Area to visit the project site.

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Foxx said, “If you don’t have local funds to match federal dollars, you can’t get past go on these projects.”

Funds are tight, so Santa Clara County is proposing a half-cent sales tax that would directly fund the project.

If the measure is shot down, the whole plan is derailed.

Santa Clara County Supervisor Cindy Chavez said, “If it doesn’t pass, we won’t have a way to fund the second phase of BART into downtown San Jose and into Santa Clara.”

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If it goes through, the BART extension will mean tens of thousands of new riders for the county’s transit system, which has seen ridership plummet over the past decade.

Santa Clara County leaders are asking voters to approve the half-cent sales tax, known as measure B, that would generate $1.5 billion for BART and pave the way for the transit system to extend to Santa Clara.

The total number of trips on VTA buses and trains has dropped a staggering 23 percent since 2001.

But VTA officials say BART could be a game changer.

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VTA spokesperson Brandi Childress said, “They need fast. They need efficient. They need a system that works for them in order to leave their cars at home. And that’s what we’re going to be doing with the delivery of BART to Silicon Valley.”