Pub. Util. Code, § 102331

(a) In addition to revenues and receipts from other sources, the board may levy and collect a property tax in the entirety of, or a portion of, the incorporated and unincorporated territory. The board may impose different rates of taxation in areas within the district. Authority exercised pursuant to this subdivision shall be subject to any applicable constitutional requirements.

(b) If the tax only applies to a portion of an area of the district, both of the following shall apply to the imposition of the tax:

(1) The incorporated area of each city and of contiguous cities within the district shall be either wholly included within that portion or wholly excluded from that portion. For purposes of this paragraph, “contiguous cities” means two or more cities with shared borders.

(2) The entire unincorporated area of the district shall either be wholly included within that portion or wholly excluded from that portion.

(c) The proceeds of the property tax shall be used to provide, within the areas taxed, for the improvement or acquisition of any real property needed for transportation purposes.

(d) An election to impose a property tax as described in this section shall only include the voters of those portions of the area of the district in which the property tax will be imposed.