California Code, Streets and Highways Code - SHC § 27510

(a) One director, representing Del Norte County, one director, representing Mendocino County, and one director, representing Napa County, appointed by the board of supervisors of the respective represented county.

(b) Four directors, representing Marin County, appointed by the board of supervisors thereof. One of the directors shall be an elected member of the board of supervisors, another of the directors shall be an elected member of a city council of a city within Marin County, and shall be designated by the Marin Council of Mayors and Councilmen and another of the directors shall be a member of the general public.

(c) Three directors, representing Sonoma County, appointed by the board of supervisors thereof. One of the directors may be an elected member of the board of supervisors, and another of the directors shall be an elected member of a city council of a city within Sonoma County, and shall be designated by the Mayors' and Councilmen's Association of Sonoma County.

(d) Nine directors, representing the City and County of San Francisco, eight of whom shall be appointed by the board of supervisors thereof, and one of whom shall be appointed by the mayor thereof by an order of appointment, a certified copy of which shall be immediately forwarded to the Secretary of State. Four of the directors shall be elected members of the board of supervisors.