California Code, Public Utilities Code - PUC § 130406

(a) If the commission decides to adopt a retail transactions and use tax pursuant to this article, the commission shall review and assess the needs for the public transportation purposes specified in Section 130405.  As part of this review and assessment, the commission shall solicit proposals for public transportation purposes from the Department of Transportation, the county, and the cities therein, and all public transit operators within the county.  The commission shall adopt a procedure for evaluating these proposals in consultation with the Department of Transportation, the county, and the cities therein, and all public transit operators within the county.

(b) Based on the evaluation, the commission shall prepare a plan for the expenditure of the revenues expected to be derived from the tax provided for in this article, together with other federal, state, and local funds expected to be available for transportation improvements, for a period of 15 years.

(c) The expenditure plan shall include projections of revenues and expenditures for capital, maintenance, and operations purposes for categories of transportation facilities, including, but not limited to, freeways, arterial roads, local streets and roads, and transit.

(d) The commission shall not adopt the expenditure plan until it has received the approval of the board of supervisors and the city councils representing both a majority of the cities in the county and a majority of the population residing in incorporated areas of the county.  Before adoption of an expenditure plan, the commission shall also conduct public hearings on that plan.

(e) The expenditure plan shall be finally adopted prior to the call of the election provided for in Section 130401.  An amendment to the expenditure plan subject to protest pursuant to paragraph (3) of subdivision (c) of Section 130407 shall be finally adopted by the commission after approval of the board of supervisors and the cities as specified in this section and public hearings on the amendments, and the amendment is effective upon that final adoption by the commission.