(1) In districts comprised of more than one member city, the legislative authorities of any member city that is located in a county having a population of more than one million five hundred thousand may petition the district to provide supplemental transportation improvements.

(2) Upon receipt of a petition as provided in subsection (1) of this section for supplemental transportation improvements that are to be fully funded by the petitioner city, including ongoing operating and maintenance costs, the district must:

(a) Conduct a public hearing, and provide notice and opportunity for public comment consistent with the requirements of RCW 36.73.050(1); and

(b) Following the hearing, if a majority of the district's governing board determines that the proposed supplemental transportation improvements are in the public interest, the district shall adopt an ordinance providing for the incorporation of the supplemental improvements into any existing services. The supplemental transportation improvements must be in addition to existing services provided by the district. The district shall enter into agreements with the petitioner city or identified service providers to coordinate existing services with the supplemental improvements.

(3) Upon receipt of a petition as provided in subsection (1) of this section for supplemental transportation improvements proposed to be partially or fully funded by the district, the district must:

(a) Conduct a public hearing, and provide notice and opportunity for public comment consistent with the requirements of RCW 36.73.050(1); and

(b) Following the hearing, submit a proposition to the voters at the next special or general election for approval by a majority of the voters in the district. The proposition must specify the supplemental transportation improvements to be provided and must estimate the capital, maintenance, and operating costs to be funded by the district.

(4) If a proposition to incorporate supplemental transportation improvements is approved by the voters as provided under subsection (3) of this section, the district shall adopt an ordinance providing for the incorporation of the supplemental improvements into any existing services provided by the district. The supplemental improvements must be in addition to existing services. The district shall enter into agreements with the petitioner city or identified service providers to coordinate existing services with the supplemental improvements.

(5) A supplemental transportation improvement must be consistent with the petitioner city's comprehensive plan under chapter 36.70A RCW.

(6) Unless otherwise agreed to by the petitioner city or by a majority of the district's governing board, upon adoption of an ordinance under subsection (2) or (4) of this section, the district shall maintain its existing public transportation service levels in locations where supplemental transportation improvements are provided.