(a) A county transportation expenditure plan shall be prepared for the expenditure of the revenues expected to be derived from the tax imposed pursuant to this chapter, together with other federal, state, and local funds expected to be available for transportation improvements, for the period during which the tax is to be imposed.
(b) A county transportation expenditure plan shall not be adopted until it has received the approval of the board of supervisors and of the city councils representing both a majority of the cities in the county and a majority of the population residing in the incorporated areas of the county.
(c) The plan shall be adopted prior to the call of the election provided for in Section 180201.