Riggs Road Traffic Interchange at SR 347

Pictured below: A bird's-eye view of the existing Riggs Road and SR 347 intersection.

Background

The project originated with a study conducted by MAG on the SR 347 Corridor, which identified the need to separate SR 347 from Riggs Road traffic. Further study was done by ADOT, which evaluated alternatives for the interchange design. More information on the project scoping done in the study phase can be found below in the Public Involvement section. 

Selected Alternative

Following extensive agency and public involvement to seek input on potential design concept alternatives for the interchange, which included public meetings in August 2024, the project team selected the design alternative to move forward. More information about the interchange design, which was presented at the public meetings as Alternative B1, is provided below.

The interchange will feature a tight diamond design where the on-and-off ramps are in a diamond shape. 

The key elements of this design are:

• SR 347 traffic will travel on a new bridge over Riggs Road, which will remain at grade level.
• SR 347 will be shifted to the east and Riggs Road will be shifted to the south to avoid the Gila River Indian Community electrical substation.
• SR 347 will have two lanes in each direction. 
• The project will be designed and constructed to allow for future widening to three lanes in each direction.
• Riggs Road will have two lanes in each direction, as well as a left-turn and right-turn lane in each direction to access SR 347.

More information about the alternatives considered and the evaluation criteria can be found in the Project Documents section below.

Project Documents

Final Scoping Design Concept Report (DCR)
DCR Appendix A: AASHTO Report
DCR Appendix B: Alternatives Considered
DCR Appendix C: Roll Plots of Refined Alternatives
DCR Appendix D: Typical Sections of Recommended Alternative
DCR Appendix E: Roll Plots of Recommended Alternative
DCR Appendix F: Drainage Memorandum
DCR Appendix G: Final Traffic Report
DCR Appendix H: Construction Sequence
DCR Appendix I: Access Control
DCR Appendix J: Draft Bridge Selection Report
DCR Appendix K: ADA Report
 

Public Involvement

ADOT and its project partners held two in-person meetings in August 2024 to present and seek input on proposed improvements to the SR 347 corridor, between I-10 and the city of Maricopa, as well as the SR 347 corridor widening project. 

The meetings were held in the city of Maricopa and the Gila River Indian Community to provide an opportunity for Community members to give input and ask questions about the project.

Documents and Presentations

Public Meeting Presentation (English)
Public Meeting Script (English)
Public Meeting Display Boards (English)
Public Meeting Presentation (Spanish)
Public Meeting Script (Spanish)
Public Meeting Display Boards (Spanish)
Riggs Road Alternatives Visual Simulations 

Schedule

Final design of the project began in January 2025 and is scheduled to be completed in early 2026. The project would be ready to start construction in 2026, pending availability of funding.

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