(a) As an alternative to the procedure set forth in Section 7285, the board of supervisors of any county may levy, increase, or extend a transactions and use tax throughout the entire county or within the unincorporated area of the county, as applicable, for specific purposes. The tax may be levied, increased, or extended at a rate of 0.125 percent, or a multiple thereof, for the purpose for which it is established, if all of the following requirements are met:

1. (1) The ordinance proposing that tax is approved by a two-thirds vote of all members of the board of supervisors and is subsequently approved by a two-thirds vote of the qualified voters of the entire county if levied on the entire county or the unincorporated area of the county if levied on the unincorporated area of the county, voting in an election on the issue.
2. (2) The transactions and use tax conforms to the Transactions and Use Tax Law Part 1.6 (commencing with Section 7251).
3. (3) The ordinance includes an expenditure plan describing the specific projects for which the revenues from the tax may be expended.