Ariz. Rev. Stat. § 28-6705 – Public road and street maintenance

A. The board of supervisors may spend public monies for maintenance of public roads and streets other than legally designated state and county highways located without the limits of an incorporated city or town. Before spending public monies under this section, the roads or streets shall be either:
1. 1. Laid out, opened and constructed in accordance with standard engineering road specifications adopted by the board of supervisors without cost to the county.
2. 2. Completed pursuant to a plat that is approved pursuant to sections 11-802 and 11-822.
B. The board of supervisors may spend public monies for maintenance of public roads and streets that were laid out, constructed and opened before June 13, 1990 even if the roads and streets were not constructed in accordance with subsection A of this section.
C. Maintenance of a public road or street does not include purchasing or laying cement. To reduce long-term maintenance costs for maintenance authorized by this section, the board of supervisors may spend monies to add rock products, gravel and processed materials to the base of the roads and streets. Petroleum based or nonpetroleum based products may be used in the maintenance and repair of unpaved roads, alleys and shoulders identified pursuant to section 9-500.04 or 49-474.01 or unpaved roads, alleys and shoulders in any county where the control officer as defined in section 49-471 certifies to the board of supervisors that emissions from such roads, alleys or shoulders may endanger compliance with the national ambient air quality standard as defined in section 49-401.01.