Frequently asked questions

Chapter 3 of the Final Environmental Impact Statement (FEIS) states traffic projections estimate approximately 117,000 to 190,000 vehicles daily would use the South Mountain Freeway in 2035.

Air quality impacts were estimated through sophisticated computer modeling based on predictions of the amount and nature of traffic under worst-case scenarios. The emissions models are based on extensive emissions testing that the U.S. Environmental Protection Agency (EPA) has conducted on thousands of vehicles representative of the ages and models of the vehicle fleet on the roads today.

The carbon monoxide and particulate matter (PM10) analyses demonstrated that the freeway will not contribute to any new localized violations, increase the frequency or severity of any existing violation, or delay timely attainment of the National Ambient Air Quality Standards or any required interim emissions reductions or other milestones.

Since ozone is a regional pollutant, there is no requirement to analyze potential impacts and no possibility of localized violations of ozone to occur at the project level. The Maricopa Association of Governments is responsible for developing plans to reduce emissions of ozone precursors in the Maricopa area. The South Mountain Freeway is included in the Regional Transportation Plan that has been determined by the U.S. Department of Transportation to conform to the State Implementation Plan on February 12, 2014.

The emission modeling developed for the freeway showed that for the mobile source air toxics study area, there would be little difference in total annual emissions of mobile source air toxics emissions (less than a 1 percent difference) in 2025 and 2035. In addition, beginning in 2017, the new EPA Tier 3 vehicle and fuel standards will reduce tailpipe and evaporative emissions and reduce mobile source air toxics.

The Record of Decision discusses the air quality analyses in greater detail.

While efforts to study alternatives on Community land were attempted, the Community has long held a position of not allowing the freeway to be located on its land. For example, a coordinated referendum of Community members to favor or oppose construction of the freeway on Community land or to support a no-build option occurred in February 2012, and Community members voted in favor of the no‑build option. Therefore, the freeway cannot be located on Community land.

The study did consider a variety of transportation alternatives, modes, and strategies that would fit into the Regional Transportation Plan, including transit. The freeway option was determined to best meet the purpose and need for the project, following an extensive screening process which included evaluation of additional benefits such as system linkage, regional mobility, and consistency with regional and local long-range plans.

Public input was a vital component during the environmental study phase and was solicited from project inception through key milestones in the Draft and Final Environmental Impact Statement (EIS) processes. The interests and needs of the public, along with all other social, economic and environmental issues and impacts, were fully analyzed during the study phase of the project. More information about the entire public involvement process up to publication of the Final EIS is available in Chapter 6, Comments and Coordination, of the Final EIS.

The route for the freeway was determined through a multidisciplinary process to identify a range of reasonable alternatives that were studied in detail in the Environmental Impact Statement. The study process involved identifying, comparatively screening, and eliminating alternatives based on:

• input from the public
• a comparison of alignment alternatives
• surrounding communities, resources, and other factors
• the historical context of the freeway
• projected regional traffic conditions with and without a freeway

The final decision on the route for the freeway was determined by ADOT, the FHWA and MAG, the transportation authority and planning agency for the region. As a corridor that is part of a comprehensive regional plan developed by MAG, ADOT serves as the agency responsible for implementation of the plan, with FHWA providing the federal oversight required to access federal funds. FHWA is the lead federal agency responsible for implementing the requirements of the National Environmental Policy Act, the governing federal law, and was responsible for the ultimate decision in selecting a route for the freeway.

The SMF has been a critical part of the MAG Regional Freeway Program since it was first included in funding approved by Maricopa County voters in 1985. The SMF was also part of the Regional Transportation Plan funding passed by Maricopa County voters in 2004 through Proposition 400. The SMF is a key component of the region’s adopted multimodal transportation plan and the Regional Freeway and Highway System and is the last piece to complete the Loop 202. The Federal Highway Administration issued a Record of Decision (the final decision-making document for the project) selecting a build alternative on March 5, 2015.

The 40th Street, Estrella Drive and Vee Quiva Way interchanges provide the Gila River Indian Community direct access to and from the freeway. The Gila River Indian Community is responsible for connecting to the traffic interchanges, in coordination with appropriate jurisdictions.

The South Mountain Freeway will be constructed as an eight-lane freeway (three general purpose lanes and one HOV lane in each direction). There are no current plans to widen the freeway in the future.

ADOT no longer paves its highway bridges with rubberized asphalt. This is because the rubberized asphalt must be removed and replaced each time a bridge needs to be inspected or if a repair must be made. By not paving bridges with rubberized asphalt, ADOT reduces costs, as well as the need to close or restrict freeways for asphalt removal or replacement. And because rubberized asphalt is a temperature-sensitive product, bridges could be repaved only during optimal conditions that occur twice a year (spring and fall).