Helping ADOT Scale New Heights with South Mountain Freeway Project

We are lead federal environmental litigation counsel for the construction of the $1.8 billion South Mountain Freeway Project in Phoenix, Arizona. It is the largest single highway project in Arizona history.

The South Mountain Freeway project adds 22 miles of freeway to the existing Phoenix metropolitan transportation system. It provides a long-planned direct link between the East Valley and West Valley and a much-needed alternative to I-10 through downtown Phoenix. The project is the last piece to complete the Loop 202 system in the Phoenix metropolitan area.

First, in a 2016 decision of national importance to the transportation community, the U.S. District Court for the District of Arizona rejected National Environmental Policy Act (NEPA) challenges and Section 4(f) challenges to the 22-mile South Mountain Freeway Project in southwestern Phoenix, Arizona in the matter Protecting Arizona’s Resources and Children v. Federal Highway Administration, No. CV-15-00893 (D. Ariz. Aug. 19, 2016). That decision had implications for other transportation projects because it affirmed that transportation agencies may (1) define a project’s purpose and need and the range of alternatives based on the objectives described in an approved regional transportation plan, and (2) in certain circumstances, rely on the socioeconomic projections created by the metropolitan planning organization to form the basis of both the Action and No-Action Alternatives.

Then, in December 2017, the Ninth Circuit Court of Appeals affirmed the district court rejecting plaintiffs’ challenges to the project in Protecting Arizona’s Resources and Children v. Federal Highway Administration, No. 16-16586 (9th Cir. Dec. 8, 2017). Issues included NEPA range of alternatives, Section 4(f) of the Department of Transportation Act, air quality impacts relating to impacts on sensitive populations, and historic and cultural resource impacts. The decision was the latest ruling by the Ninth Circuit concluding that transportation agencies may (1) define a project’s purpose and need statement and the range of alternatives based on the objectives described in an approved regional transportation plan (RTP), and (2) rely on the socioeconomic projections adopted by the metropolitan planning organization to form the basis of both the Action and No-Action Alternatives.

Major construction began in early 2017 and completed in 2020. Construction includes 40 bridges and 15 traffic interchanges with on-and-off ramps, including the 32nd Street and Ivanhoe Street interchanges that were added to the project.