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The Spine Study: Interstate-10 and Interstate-17 Corridor Master Plan


MARCH 2017
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We had great turnout at public open houses held January 24, 25 and 31. We encourage you to navigate our interactive map of the Corridor Master Plan Recommendations.

Linked below are public meetings materials.

Study Overview

The Maricopa Association of Governments (MAG), in partnership with the Federal Highway Administration (FHWA) and the Arizona Department of Transportation (ADOT), launched this study to develop a Corridor Master Plan for the Interstate 10 (I-10) and Interstate 17 (I-17) corridor. This corridor is referred to as the “Spine,” because it serves as the backbone for transportation in the metropolitan Phoenix area. In fact, the corridor handles more than 40 percent of all daily freeway traffic in the region.

The Spine Study effort is analyzing various long-term strategies to improve mobility in the corridor. The study is evaluating the full range of transportation modes and concepts to identify the best multimodal solutions. These long-term solutions are envisioned as a combination of traditional methods, new technology, and increased use of transit (such as buses.) The key outcome of the Spine Study will be a detailed strategy to manage traffic in the I-10 and I-17 corridors through 2040. Study recommendations will be programmed in the MAG Regional Transportation Plan and Transportation Improvement Program.

Pubpic open house participants in Guadalupe, AZ

The current MAG Regional Transportation Plan allocates $1.47 billion for the Spine Corridor. This amount includes funding for any identified near-term improvements, in addition to longer range improvements. The Spine Study will identify how to best use these funds to achieve the greatest benefit to the region. It will also define funding shortfalls of the preferred corridor improvement approach so that additional funding allocations can be identified.

I-10/I-17 Spine Corridor

The 31-mile Spine corridor begins at the I-17/Loop 101 (North Stack) interchange and continues south and east to the I-10/I-17 (The Split) interchange. The corridor continues east and south along I-10 to the interchange with Loop 202 (Pecos Stack).

Public Engagement

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.Use the interactive “online comment viewer” to see all pins and comments made along the Spine Study area.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.

Study Documents

Previous Environmental Studies on I-10 and I-17

In recent years, ADOT and FHWA were 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 looked at 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 for either corridor. 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 will be folded into the new Corridor Master Plan.

Contact Information

You can contact the study team using any of the means shown below.

  • Phone: 602-759-1916
  • Email:
  • Mail: 302 N. 1st Avenue, Suite 200, Phoenix, AZ 85003

MAG fully complies with Title VI of the Civil Right Act of 1964 and related statutes and regulations in all programs and activities. For more information on rights afforded under Title VI, relevant activities at MAG, or if you feel these rights have been violated, please click here or call (602) 254-6300.

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