Enhancing Safety and Regional Mobility on I-10 in Arizona

Unique Design

Reconstructed both the existing diamond traffic interchanges to be diverging diamond interchanges (DDIs)—two of the first DDIs to be implemented in Arizona at the time

Strategic Traffic Management

Engineered solutions for short-term closures on the interstate and local streets to reduce impacts on businesses and alleviate congestion

Stakeholder Collaboration

Coordinated with a variety of local stakeholders, including the City of Buckeye, Maricopa Association of Governments, and Maricopa County’s Department of Transportation and Flood Control District

The City of Buckeye, Arizona, has experienced recent population growth, and with it, new hotels, travel centers, and other businesses have developed along Interstate 10 (I-10) from State Route (SR) 85 to Verrado Way. This well-traveled eight-mile stretch of I-10 serves as a gateway welcoming residents and visitors to the city, yet the highway’s existing infrastructure in each direction couldn’t support the increased traffic, causing congestion and reducing vehicular safety.

To increase capacity and improve traffic operations and safety, Kimley-Horn prepared a Design Concept Report (DCR), environmental documentation, and final design to reconstruct the two traffic interchanges (TIs) at Miller Road and Watson Road and add two new general-purpose lanes (GPLs) on I-10. Additionally, the City of Buckeye’s major arterial streets, Miller Road, and Watson Road were all widened to six lanes at the TI.

Providing Innovative Roadway Services for ADOT

Our project services included preparing design technical reports, public involvement with residents of the City of Buckeye, and obtaining environmental, utility, and right-of-way clearances. We performed services in the following disciplines:

The previous TIs were a standard compact diamond configuration; however, we designed new diverging diamond interchanges (DDIs) at both locations, which were some of the first to be implemented in Arizona. DDIs allow traffic shifting to the left side of the crossroads eliminating the need for left turns across opposing traffic, minimizing the potential for collisions.

We designed the TIs to increase safety, control access, and ease traffic congestion, which included helping an adjacent hotel navigate an access issue. We met with the owners and, in conjunction with ADOT, helped recommend an alternative option in the form of a new access road that allowed hotel patrons and workers to access the hotel without impacting traffic on the TIs.

Engaging Stakeholders for I-10 Expansion

Our team collaborated with multiple stakeholders, including the City of Buckeye, Maricopa County Department of Transportation, Maricopa County Flood Control District, Maricopa Association of Governments, and various utility companies on this project. Since the interstate went over a flood control retarding structure that couldn’t be disturbed, we worked specifically with Maricopa County Flood District to obtain flood control use and right-of-way use permits to design and construct improvements to I-10 and Miller Road.

Additionally, we coordinated public meetings with the City of Buckeye in collaboration with ADOT, supporting ADOT’s presentation with pre-prepared graphics, slide decks, display boards, and videos and helping answer questions from the public. Our team also attended HOA meetings to present the project, address concerns, and provide information about the scope, schedule, and traffic detours. Based on public input, we determined that adding 15- to 20-foot sound walls between the

freeway and subdivision would help mitigate noise concerns for the residents. Finally, to meet the City’s requirements, we designed landscaping and aesthetics for the new bridge structures and sound walls, such as bridge and wall rustication and landform graphics.

Minimizing Disruptions Through Phased Construction

Because the City of Buckeye is already constrained with the White Tank Mountains on one side of the interstate limiting options for traffic detours, our team worked closely with the City’s staff and communications team to manage traffic during construction. To mitigate impacts to local businesses from lengthy road closures, our team prepared comprehensive construction phasing and maintenance of traffic plans and specifications. We also implemented incentives for the contractors to construct both TI ramps and crossroads with an expedited schedule.

Enhancing the Region’s Mobility and Safety

The reconstruction of the TIs at Miller Road and Watson Road and the addition of one new GPL in each direction have significantly increased the capacity of I-10 and improved its traffic operations, offering greater regional mobility and improved access to residential and commercial developments for the growing Buckeye community. With the success of the project, ADOT has since trusted Kimley-Horn for DCR and final design for another TI on I-10 within the City of Buckeye limits, further strengthening our partnership and our commitment to enhance mobility and safety for those who call this region home.