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.

The Maricopa County Transportation Excise Tax, often referred to as the “1/2 cent sales tax” is levied upon business activities in Maricopa County, including retail sales, contracting, utilities, rental of real and personal property, restaurant and bar receipts, and other activities. Transportation excise tax revenues are deposited in the Maricopa County Regional Area Road Fund (RARF) which is administered by the Arizona Department of Transportation. These revenues were the principal source of funding for the Regional Freeway System in Maricopa County and were dedicated by statute to the purchase of right-of-way, design and construction of new freeways, widening of existing freeways and highways, improvements to the arterial street system, regional bus service and high capacity transit services such as light rail.

This is Maricopa County's long-range plan for transportation. This plan was last produced in 1997. The Maricopa County Department of Transportation has undertaken the process of updating the Transportation System Plan because much has happened in Maricopa County since 1997. This updated TSP establishes an organized approach to the planning, design and construction of Maricopa County's transportation system through 2026.