California Streets and Highways Code
Within five days after the issuance of the certificate of incorporation, the Secretary of State shall notify the boards of supervisors of each of the counties in which any portion of the territory of the district is located, of the incorporation of the district.
Within 30 days after the receipt of the notice of incorporation of the district each of the boards of supervisors so notified shall appoint the persons to represent the county on the board of directors of the district.
Those directors appointed by the board of supervisors of a county shall be appointed by resolution of the board of supervisors, and a copy of the resolution shall be filed with the clerk of the board of supervisors, and a certified copy of the resolution shall be immediately forwarded to the Department of Transportation.
All directors shall serve at the pleasure of the appointing authority; provided, that notwithstanding this section and Section 27122, any director in office on the effective date of this section may continue to serve on the board until the expiration of the term for which he was appointed.
Each appointing authority shall review its appointment or appointments to the board in January every two years, and indicate its desire to retain such director or directors by affirming such retention by the adoption of a resolution, or, in the case of the Mayor of the City and County of San Francisco, by the issuance of a declaration, to that effect.
Any vacancy in the board shall be filled by appointment by the appointing authority which originally appointed the director whose position has become vacant.