Sts. & Hy. Code, § 1550.1

The board of supervisors may form special road maintenance districts in unincorporated areas of the county wholly outside of incorporated cities. Formation of these districts may be ordered by the board when in its opinion additional road funds are necessary to properly maintain highways and roads in specific unincorporated areas of the county. These districts shall be formed by order of the board setting forth the boundaries thereof. A district shall be in existence until the board shall by its order discontinue the district. If a district is to be formed, the board shall set a date for a hearing on the formation. This hearing shall not be held in less than three weeks after the date of the order for the hearing, and prior to the date of the hearing, a notice of the hearing shall be published twice in a newspaper of general circulation in the area, and, in addition, at least three notices shall be posted in public places within the proposed district. At the hearing, protests, if any, shall be heard on the proposed formation of the district. It shall be within the power of the board to determine from the results of the hearing the necessity for the special road maintenance district, and, if it be deemed necessary, the district may be formed.