MAG along with the Federal Highway Administration (FHWA) and the Arizona Department of Transportation (ADOT), launched a study to develop a Corridor Master Plan for the I-10 and I-17 corridor. The project’s planning efforts began in April 2014 and concluded with MAG Regional Council acceptance of the project’s Recommended Alternative on May 24, 2017 into the MAG 2040 Regional Transportation Plan. On March 28, 2018, representatives from the Arizona Department of Transportation, Federal Highway Administration – Arizona Division, and the Maricopa Association of Governments, signed a Planning and Environmental Linkages (PEL) Statement summarizing the findings of the project.
The study area was the 31-mile corridor beginning at the I-17/Loop 101 (North Stack) interchange , through the I-10/I-17 (The Split) interchange, and down the 10 to the interchange with Loop 202 (Pecos Stack). This corridor is referred to as the “Spine” because it serves as the backbone for transportation in the metropolitan Phoenix area. The corridor handles more than 40 percent of all daily freeway traffic in the region.
The Spine Study analyzed long-term strategies to improve mobility in the corridor. The study evaluated the full range of transportation modes and concepts to identify the best multimodal solutions. These long-term solutions are viewed as a combination of traditional methods, new technology, and increased use of transit. The key outcome of the Spine Study is a detailed strategy to manage traffic in the I-10 and I-17 corridors through 2040. Recommendations are programmed in the MAG Regional Transportation Plan and Transportation Improvement Program.
The following document has been prepared summarizing the study process, purpose and need, public outreach, the recommended alternative, and the initial environmental findings that have been documented.
The Spine Study analyzed long-term strategies to improve mobility in the corridor. The study evaluated the full range of transportation modes and concepts to identify the best multimodal solutions. The study sought to incorporate a combination of traditional methods, new technology, and increased use of transit in order to manage traffic along these corridors through 2040.
In the spring of 2015, the MAG, in partnership with the FHWA and ADOT, held the first round of public meetings to share information about the Spine Study and obtain public comment on potential corridor improvements. Members of the public were encouraged to attend the meetings or participate by completing an online survey. Nearly 1,800 members of the community provided their comments during this process. The spring 2015 Agency and Public Involvement Summary Report is included as Appendix J of the Interstate 10/Interstate 17 Corridor Master Plan (FY 2014) Needs Assessment Report.
The initial input in 2015 helped MAG create recommendations for improvements along this corridor. These recommendations were brought to the community for feedback in 2017. In addition to great meeting attendance at our public open houses in January 2017, we had hundreds of people complete our online survey. After reviewing all the feedback received, the study team suggested the following revisions to the I-10/I-17 Corridor Master Plan Recommendations:
Ideas for corridor improvements were evaluated with the following criteria (in no particular order):
For more information on the evaluation criteria, check out Banner: How did we evaluate the options?
You can download the entire Alternatives Screening Technical Report here (218 pages, 67.7 MB), and download appendices A-E here (490 pages, 63.9 MB) and F-H here (402 pages, 69.2 MB.
ADOT and FHWA were previously developing design concept reports and environmental impact statements as part of the I-10 Corridor Improvement Study and I-17 Corridor Improvement Study. These studies examined ways to add capacity, such as general purpose lanes, to both I-10 and I-17 in the Phoenix area.
The two previous studies identified long-term improvements that would have required more funding than was available in the Regional Transportation Plan. However, the studies also identified a number of near-term improvements that will be carried forward and implemented by ADOT through a separate but parallel effort.
ADOT and MAG agreed, and FHWA accepted, the decision to rescind the studies in 2012 after it was determined that separate studies may not result in the best overall plan and that many of the studies' recommendations were not prudent. It is important to note that many of the planning, engineering and environmental information from those studies were folded into the new Corridor Master Plan.