Ariz. Rev. Stat. § 28-7652
A. The department and a county with a population of more than two million persons may enter into an intergovernmental agreement pursuant to title 11, chapter 7, article 3 for the construction of a bridge to provide direct access to commercial, residential and recreational facilities.
The agreement shall:
B. The department and the county may enter into an intergovernmental agreement pursuant to title 11, chapter 7, article 3 for the design, reconstruction and improvement of a county highway approaching and traversing a bridge constructed pursuant to subsection A of this section. The agreement shall: