SAN JOSE -- Measure B, the sales tax increase that would help bring BART to the South Bay, reached the required majority on Monday to pass. However, the Santa Clara County Registrar's office still has some 9,800 provisional ballots to count.

The tax needs a 66.67% yes vote. When polls closed on November 4, it appeared to be about a half-percentage point short of the required two-thirds majority. But provisional ballots have given it a boost in the days since the election.

Measure B would increase the sales tax in Santa Clara County by one-eighth of a cent. It would take effect once a funding agreement is in place with the Federal Transit Administration. The FTA is promising to pledge $750 million toward the $6.1 billion project, if the sales tax is enacted.

The sales tax would help cover the estimated $50 million it would cost annually to operate the extension, which would add 16 miles to BART, taking trains from Fremont all the way to Mineta San Jose Airport.