Loop 303, US 60 to El Mirage Road Traffic Interchange Alternatives Study

Overview

In June 2025, the Arizona Department of Transportation, in partnership with the Maricopa Association of Governments (MAG) and the cities of Peoria and Surprise, completed a study to determine the location and design concept for a new traffic interchange on Loop 303 between US 60 (Grand Avenue) and El Mirage Road.

The study evaluated four design alternatives, including Loop 303 interchanges at 155th, 151st and 147th avenues and Litchfield Road. These alternatives were presented for stakeholder input during a review of the Initial Project Assessment and shared with the public during a February 2025 public meeting hosted by MAG.

Upon completing a technical evaluation and incorporating public input, the study team has recommended moving forward with the 155th Avenue Traffic Interchange alternative. ADOT has published the Final Project Assessment (FPA), which includes preliminary design information and justification for recommending the Loop 303/155th Avenue Traffic Interchange alternative. The FPA can be accessed by clicking here. 

Study Area Map

Study Timeline

• February 2025: Design alternatives presented at MAG’s US 60, Loop 303 to SR 74 Corridor Study public meeting.
• February-March 2025: Public comments collected. The public comment summary can be found here.
• June 2025: 155th Avenue Interchange alternative selected.

Alternative Evaluation Criteria

The ADOT study team used several criteria to evaluate the interchange alternatives before recommending the 155th Avenue Interchange move forward for further design. Criteria included:

• Regional mobility - How well the alternative improves traffic conditions in the area and operational considerations.
• Environmental and socio-economic impacts - Potential impacts to the Beardsley Canal; visual, noise and traffic impacts to nearby residents; opportunity to connect future development; and agency and public support.
• Engineering Feasibility, Construction and Maintenance - Impacts to the McMicken Dam Outlet Channel; relocation of powerlines and other utilities; the cost and difficulty to construct; the amount of new right of way needed; and traffic impacts during construction.

All alternatives considered:

• Provide access to Loop 303 to and from the north, with no direct roadway connection to the Sun City West or Corte Bella communities. 
• Require future local roadway connections and roadway widening in some locations on local streets north of Loop 303, which vary depending on the location. These roadway improvements need to be built by local jurisdictions. 
• Require a new bridge over the McMicken Dam Outlet Channel to connect the interchange to local roadways to the north.
• May require additional right of way and drainage improvements.

Recommended Alternative: 155th Avenue Traffic Interchange

The goal of this new Loop 303 interchange at 155th Avenue is to address growing traffic volumes in the area and alleviate congestion at the existing US 60/Loop 303 traffic interchange and US 60/163rd Ave intersection.

The configuration presented in the Initial PA was located further west, aligning directly with 155th Avenue. After receiving public feedback, the study team re-evaluated this configuration and shifted the traffic interchange slightly to the east. This shift improves the new 155th Avenue interchange’s compatibility with the planned system improvements at the Loop 303/US 60 interchange.

The offset interchange at 155th Avenue north of Loop 303 allows the northbound on- and off-ramps to cross over Loop 303 to a signalized intersection located on the north side of the freeway. The southbound on- and off-ramps are extended longer than standard ramps to accommodate the position of the northbound ramps. 

Considerations

• Provides the best congestion relief on US 60 of all alternatives considered. 
  • Reduces traffic volumes 33.1% on 163rd Avenue north of US 60.
  • Reduces traffic volumes 18.1% on US 60 between 163rd Avenue and Loop 303.
  • Reduces wait times at the US 60/163rd Avenue intersection by 2.3 minutes during PM rush hour.
• Some visual and possible noise impacts from two bridges over Loop 303 near Sun City West adjacent to the golf course.
• Requires extensions of Pinnacle Peak Road, 155th Avenue and McMicken Way.

Project Schedule

Final design is expected to begin in early 2026. According to the Maricopa Association of Government's Freeway Life Cycle Program, construction is currently planned to advertise in Fiscal Year 2028.

Study Documents

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• Phone: ADOT Project Information Line: 855.712.8530
• Email: [email protected]
• Mail: ADOT Communications, 1655 W. Jackson St., MD 126F, Phoenix, AZ 85007