Update to the story below as of 1720h PST: The San Jose Mercury News is reporting that with 9800 ballots remaining, Measure B has passed the 66.67 percent mark.

The ballot initiative to fund a BART extension to San Jose may have squeaked by, KNTV was reporting this afternoon. Though initial balloting showed the measure falling short of the required two-thirds majority, mail-in ballots are turning the tide.

With 17,000 of 42,000 mail-in ballots still to be counted, the vote to fund the 22-mile BART extension with a 1/8-cent Santa Clara County sales tax was 66.61 percent yes; the measure, like any tax increase in California since the 1978 passage of Proposition 13, requires at least a 66.67 percent yes vote.

If the Bart-to-San Jose tax passes, it would complete a surprising trifecta of voter support for mass transit projects at a time when local and state budgets are tight. Earlier this month, voters in Marin and Sonoma Counties passed a rail initiative, and statewide Proposition 1A also passed, kicking off the state’s bullet train project.