Ariz. Rev. Stat. § 40-1141
The board of supervisors of each county where a metropolitan public transit authority has been established shall annually, at the time of levying other taxes, levy a metropolitan public transit authority tax on the property in the area of a public transit authority in which an additional amount is required, as determined by the authority pursuant to section 40-1140. The tax shall be at a rate sufficient to provide the additional amount. The tax shall be added to and collected in the same manner as other county taxes on the property within the area of the authority. The amount of the metropolitan public transit authority tax levied upon the property in the area of a particular authority shall be paid to the treasurer of such authority.
A.R.S. § 40-1141