The Multimodal Planning Division (MPD) of the Arizona Department of Transportation has been tasked with identifying corridors throughout the state where improvements to the transportation infrastructure supports the greatest potential commercial and economic benefits. These "Key Commerce Corridors" represent a strategic statewide approach to leverage infrastructure improvements to enhance Arizona's competitive economic position. This document presents the basis for the identification and evaluation of the Key Commerce Corridors.

The State of the System Report is a compilation of the physical inventory and status of the Maricopa County Department of Transportation’s infrastructure. It addresses roadway congestion, traffic safety, low volume road paving, bridges, and pavement conditions. Also, included are recommendations for future improvements within each of the infrastructure categories. The SOS report has been produced annually since 1998.