SR 347 Corridor Widening, I-10 to city of Maricopa

Widening SR 347 by one lane in each direction, from the northern City of Maricopa limits (MP 175.7) to I-10 (mileposts 175.1 to 189.1).
- The widening will occur within the median from the City of Maricopa to just north of Riggs Road. The northern section of the corridor, between Maricopa Road and I-10, will be widened both in the median and to the outside.
Widening existing bridges at Santa Rosa Wash, Santa Cruz Wash and Gila River to accommodate the new lanes.
Extending box/pipe culverts as needed.
Intersection improvements at Casa Blanca Road, Borgia Road (Sacate Road), Mammoth Way (Cement Plant Access Road) and Old Maricopa Road to accommodate a six lane highway.

Casa Blanca Road and Mammoth Way Intersections: Additional modifications to improve traffic flow and safety are planned at these two intersections.

Funding and Schedule

The funding for this project is coming from multiple sources:

Pinal County segment: ADOT’s adopted FY 26-30 Five Year Program includes $136.3 million in FY 27 for construction to widen SR 347 between Riggs Road and the City of Maricopa in Pinal County. This funding includes $50 million contributed by the City of Maricopa and Pinal County.
Maricopa County segment: The northern portion of the corridor (from I-10 to Riggs Road) will be funded in part through Proposition 479, a dedicated half-cent sales tax for transportation approved by Maricopa County voters in 2024, and funding is currently programmed in FY 31 in the MAG Freeway Lifecycle program. In this year’s plan update, MAG agreed to consider advancing the construction funding for the SR 347 project if funding became available for the Pinal County portion of the project, which has now been appropriated by the State and its partners. Any changes are expected to be reflected in MAG’s Transportation Improvement Program by the end of fiscal year 2026 (which ends June 30, 2026) and would then be incorporated into ADOT’s Five Year Program.

The widening project, including the Casa Blanca Road and Mammoth Way intersections, is in the design phase. The project is expected to start construction by the end of 2026.

diagram to show how the SR 347 corridor would be widened with an additional lane

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 Riggs Road traffic interchange, and answer questions.

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.