If the commission approves a draft county transportation expenditure plan, the commission shall return the draft plan to the board of supervisors for its approval and to local governments for their approval. A majority of the board of supervisors, and a majority of the local governments representing a majority of the population of the county in the incorporated areas by a majority vote of their respective councils, are required for the adoption of the draft county expenditure plan. The adopted county transportation expenditure plan shall be published by the county within 30 days after its adoption.