Ariz. Rev. Stat. § 48-5105 – Board of directors

A. A board composed of the following members shall govern the authority:
1. 1. From each municipality that enters into the authority, one elected official who is appointed by the respective governing body of the municipality.
2. 2. One county supervisor who is appointed by the county board of supervisors, if the county enters into the authority.
B. The term of each member is two years unless the member is no longer serving in the member's elected capacity, in which case the membership is vacant. The respective governing body shall fill a vacancy under subsection A of this section.
C. Each municipality or county may provide for an alternate board member who is also an elected official. Section 11-211, subsection A does not apply to a county supervisor serving on the board. If an elected official of a municipality is prohibited from serving on the board, the governing body of the municipality shall appoint an official of the municipality who is not prohibited from serving on the board.
D. The voting members of the authority are entitled to one vote for each member unless a voting member requests a weighted vote. If a weighted vote is requested, the following apply:
1. 1. Each member of the board is entitled to a percentage vote based on the proportion of the population the member represents to the total population represented by all members of the board, except as provided in paragraph 4 of this subsection.
2. 2. If a municipality is a member of the board, its proportion of the population shall be calculated on the basis of the population in the incorporated area of the municipality.
3. 3. If the county is a member of the board, its proportion of the population shall be calculated on the basis of the population in the unincorporated area of the county.
4. 4. The weighted vote of any single member shall not exceed forty per cent of the total weighted vote. If any member's proportion of the population as calculated in this subsection entitles it to a weighted vote in excess of forty per cent, the limitation on its percentage does not affect the calculation of the weighted vote of each other member.
E. For the purpose of preliminary approval of a regional public transportation system plan, the voting provisions of subsection D of this section apply, except that if a weighted vote is requested, in addition to the provisions provided in subsection D of this section relating to a weighted vote, a minimum of one-third of the voting members is also required for preliminary approval of the plan.