(a) The district board may impose a special tax pursuant to Article 3.5 (commencing with Section 50075) of Chapter 1 of Part 1 of Division 1 of Title 5 of the Government Code, subject to any applicable constitutional requirements. The special taxes shall be applied uniformly to all taxpayers or all real property within the district, or any portion of the district, except that unimproved property may be taxed at a lower rate than improved property.
(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 special tax shall be used to provide, within the area taxed, for the operation, maintenance, or acquisition of any public improvement or utility for transportation purposes.
(d) An election to impose a special tax as described in this section shall only include the voters of those portions of the area of the district in which the special tax will be imposed.