Study Process - North-South Corridor Study

The Tier 1 EIS was completed on August 20, 2021 and includes the following elements:

Tier 1 Environmental Impact Statement (EIS)

The purpose of the North-South Corridor Study Tier 1 Environmental Impact Statement was to identify a selected alternative – either a build corridor alternative or a no-build alternative – for the 55-mile corridor between U.S. 60 on the north and Interstate 10 on the south, as well as a connection to State Route (SR) 24 at Ironwood Drive. 

During the Tier 1 EIS process, ADOT evaluated potential corridor alternatives, along with the no-build alternative, for a future project alignment. The Tier 1 EIS and Record of Decision (ROD) identifies a selected build alternative for the North-South Corridor, as well as a corridor for a future proposed extension of SR 24 from Ironwood Drive to the North-South Corridor.

In 2019, the Tier 1 Draft EIS/ROD was published and made available for public review and comment, with three public hearings held in the study area.

The study team considered all comments received on the Draft Tier 1 EIS, conducted additional analysis, and coordinated with stakeholders to prepare the Final Tier 1 EIS/ROD. All comments received on the DEIS were considered and responded to in the Final Tier 1 EIS document.

The Tier 1 EIS and ROD is a combined document, and the public release of the documents concludes this phase of the study. Since this is a combined EIS and ROD, there is no formal comment period.

The Tier 1 EIS process is prescribed by the National Environmental Policy Act (NEPA). The Final Tier 1 EIS provides a Draft Phased Implementation Plan, which is a conceptual framework for how the North-South Corridor will move forward into Tier 2 studies. A Phased Implementation Plan includes smaller segments of a corridor alternative that may advance as separate, independent projects.

Tier 2 EIS studies, for shorter segments of the corridor that may advance as separate, independent projects, may now be completed. These studies would include additional analysis to further refine the selected 1,500-foot North-South corridor to identify a recommended freeway alignment and the location of interchanges, bridges and other design features, and will include opportunities for public review and comment.

ADOT is considering all funding options to move the proposed North-South Corridor through the next phase of the study process and eventually to construction.

North South Corridor Environmental Review Process