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

Overview

The Arizona Department of Transportation, in partnership with the Maricopa Association of Governments (MAG) and the cities of Peoria and Surprise, is studying a potential new traffic interchange on Loop 303 between US 60 and El Mirage Road. This potential new interchange would address growing traffic demand and high traffic volumes in the area, and alleviate some of the congestion at the existing US 60/Loop 303 traffic interchange and US 60/163rd Ave intersection.

This study will evaluate four alternatives for the location and design concept of a new traffic interchange between US 60 and El Mirage Road that will serve communities north of Loop 303 and east of US 60. A recommended interchange alternative will be identified for further design, once funding becomes available. 

All alternatives being 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. 
• Would 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 would need to be built by the 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. 

The study will develop conceptual plans for the recommended interchange alternative and will be used for regional planning and programming of design and construction funding. 

Interchange alternatives under consideration include:

Loop 303 at 155th Avenue

• This alternative features a loop ramp configuration and braided ramps. 
  • Northbound Loop 303 traffic exits onto a new bridge over Loop 303 that loops toward 155th Avenue, and  returns to ground level on the north side at 155th Avenue. 
  • Northbound Loop 303 traffic from 155th Avenue enters via a new bridge over Loop 303.
  • Southbound Loop 303 traffic exits under the loop ramp structure to 155th Avenue.  
  • Traffic from 155th Avenue enters southbound Loop 303 on a standard on-ramp. 
• This design allows free-flow traffic to and from Loop 303 without the need for traffic signals at the interchange. This is due to the northbound on-ramp and southbound off-ramp crossing under the loop structure on braided ramps. 

Considerations

• Provides the best congestion relief on US 60 of all the alternatives being considered. 
  • Reduces traffic volumes 33.1% on 163rd Ave. 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.
• Visual and potential noise impacts from two bridges over Loop 303 near Sun City West adjacent to the golf course.
• Requires extensions of McMicken Way and 155th Avenue.

Loop 303 at 151st Avenue

• This alternative features an offset traffic interchange where the northbound on- and off-ramps cross over Loop 303 on new bridges, then connect with the southbound off- and on-ramps at a signalized intersection on the north side of the freeway.

Considerations

• Provides moderate congestion relief on US 60. 
  • Reduces traffic volumes 20.7% on 163rd Ave. north of US 60.
  • Reduces traffic volumes 12% on US 60 between 163rd Avenue and Loop 303.
  • Reduces wait times at the US 60/163rd Avenue intersection by 2.1 minutes during PM rush hour.
• Visual and potential noise impacts from two bridges over Loop 303 near the Sun City West community (adjacent to homes and golf course).
• Includes extensions of McMicken Way and 151st Avenue.

Loop 303 at 147th Avenue

This alternative features an offset interchange where the northbound on- and off-ramps cross over Loop 303 on new bridges, then connect with the southbound off-and on ramps at a signalized intersection on the north side of the freeway.

Considerations

• Provides some congestion relief on US 60. 
  • Reduces traffic volumes 14.2% on 163rd Ave. north of US 60.
  • Reduces traffic volumes 8.7% on US 60 between 163rd Avenue and Loop 303.
  • Reduces wait times at the US 60/163rd Avenue intersection by 2 minutes during PM rush hour.
• Visual and potential noise impacts from two bridges over Loop 303 near the Sun City West community.
• Requires extensions of McMicken Way and 147th Avenue.

Loop 303 at Litchfield Road

• This alternative features a standard diamond traffic interchange, with all ramps connecting directly to Litchfield Road.

Considerations

• Provides some congestion relief on US 60. 
  • Reduces traffic volumes 9.1% on 163rd Ave. north of US 60.
  • Reduces traffic volumes 5.8% on US 60 between 163rd Avenue and Loop 303.
  • Reduces wait times at the US 60/163rd Avenue intersection by 1.9 minutes during PM rush hour.
• Visual and potential noise impacts from one bridge over Loop 303 near the Corte Bella community.
• Requires a new segment of Litchfield Road that would connect to Happy Valley Road.

Alternatives Evaluation Criteria

The ADOT study team will be using several criteria to evaluate the interchange alternatives and recommend an interchange alternative to move forward for further design. Those include:

• 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.

We want to hear from you!

As part of this study, ADOT is collecting feedback on the alternatives from the public. 
Please complete this brief survey by March 24, 2025: azdot.gov/Loop303TIAlternativesSurvey

Study Schedule

The study team anticipates selecting the interchange alternative in spring 2025. There is currently not an expected timeframe or funding for construction of a new interchange. 

Stay Informed

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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