Spine Corridor Study I-10 I-17

Study Overview

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. 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.

I-10 I-17 Corridor Map
Click to view The larger version of this image.

The Spine Study analyzes 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 viewed as a combination of traditional methods, new technology, and increased use of transit. 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. Recommendations will be programmed in the MAG Regional Transportation Plan and Transportation Improvement Program.

The MAG Regional Transportation Plan allocates $1.47 billion for the Spine Corridor. This includes funding for any identified near-term improvements in addition to longer range improvements. The 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 corridor begins at the I-17/Loop 101 (North Stack) interchange and continues to the I-10/I-17 (The Split) interchange. The corridor continues along I-10 to the interchange with Loop 202 (Pecos Stack).

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. With this signature, the project has concluded. 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.

Recent Project Presentation

On March 29, 2018, the MAG and HDR Consultant project managers made a presentation on their lessons learned on conducting this effort at the 67th Arizona Conference on Roads and Streets in Tucson, Arizona. The following is a link to that presentation.

Public Meeting Feedback

In addition to great meeting attendance at our public hopen 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:

  • Bicycle/Pedestrian Bridge over I-17 at Osborn Road or Grand Canal: Based on considerable feedback during the comment period against this improvement, the recommendation to construct a bicycle and pedestrian bridge over the freeway as outlined in Phoenix's 2014 Comprehensive Bicycle Master Plan was removed pending guidance from the City of Phoenix.
  • I-10 and Sky Harbor Circle North Direct High Occupancy Vehicle (DHOV) Ramps: Based on recent planning developments related to the western entrance to Phoenix Sky Harbor Airport, the idea to construct DHOV ramps within the median of I-10 to Sky Harbor Circle North was removed from the recommendations.
  • I-17 and Glendale Avenue Interchange Improvement: Based on feedback received during the comment period, the reconfiguration of I-17/Glendale Avenue into a high-capacity traffic interchange was added to the recommendations. This could better accommodate large east-west arterial movements on Glendale Avenue and improve bike and pedestrian safety.
  • Bicycle/Pedestrian Bridge over I-10 at Knox Road: Based on feedback received during the comment period, a bicycle/pedestrian bridge over I-10 was added at Knox Road to support the BIKEiT Seat Route bike boulevard as outlined in Tempe’s 2015 Transportation Master Plan.

We encourage you to navigate our interactive map of the Corridor Master Plan Recommendations, which includes updates to the recommendations as outlined above. The revised recommendations was presented to MAG committees with anticipated adoption of the I-10/I-17 Corridor Master Plan by Regional Council in May, 2017.

Spine Study Public Meeting
Public open house participants in Guadalupe, AZ

Public Meetings Materials from the January 2017 Meetings.

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

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.

Previous Environmental Studies on I-10 and I-17

Recently, 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 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 will be folded into the new Corridor Master Plan.

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About MAG

The Maricopa Association of Governments (MAG) is a Council of Governments (COG) that serves as the regional planning agency for the metropolitan Phoenix area.

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Get in Touch

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    Phoenix, Arizona 85003

  • Phone: (602) 254-6300

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  • Email: mag@azmag.gov