The I-10 Broadway Curve Improvement Project, Arizona’s largest urban freeway reconstruction project, was completed this past June. It now reduces congestion and improves commutes for over 300,000 daily drivers. The Broadway Curve Constructors, a joint venture of Pulice, FNF Construction, and Flatiron, delivered this vital project for the greater Phoenix community. The following article was written by the American Society of Highway Engineers.
How would you construct one of Arizona’s busiest freeway corridors, serving hundreds of thousands of vehicles and thousands of businesses daily, while keeping traffic moving and maintaining public trust? That was the challenge for Arizona Department of Transportation (ADOT) as it launched the I-10 Broadway Curve Improvement Project in late 2021. It was the largest urban freeway reconstruction project in the state’s history.
Spanning from the southeastern Phoenix metropolitan area to the heart of the city near Phoenix Sky Harbor International Airport, the project area is a vital connection for commuters, freight traffic and visitors. The corridor handles more than 300,000 vehicles per day. It is a linchpin for regional mobility, connecting people across the valley and the region.
From the beginning, the project’s goals were clear: to improve traffic flow, enhance safety for all roadway users and accommodate future growth.
Key features included:
- widening I-10 to add new general purpose and high-occupancy vehicle lanes
- constructing or widening 21 bridges, including the major freeway interchanges at US 60 and SR 143
- introducing Collector-Distributor (CD) roads to separate local and through traffic, reducing weaving and congestion
- building new multiuse bridges and widening existing crossings for pedestrians, cyclists and equestrians
Recognizing the complexity of the project, ADOT used a Public-Private Partnership (P3) and Design-Build delivery model to leverage private sector innovation through alternative technical concepts and a best value selection. The P3 process allowed ADOT to accelerate delivery, better manage risk and assign tenant relocations to the developer to clear the Right of Way needed for construction.
Balancing risk and innovation
From the environmental study through final construction, coordination between ADOT and its regional partners was paramount to the success of the project. Early in the process, the project team conducted a series of risk workshops with its federal, state, regional and local partners to proactively identify challenges and find ways to mitigate them.
A key risk identified was the potential for construction to create disruptions for motorists, businesses and others in the corridor. Mitigating this required foresight, collaboration and meticulous planning. Construction was intentionally phased to maintain as many lanes as possible during peak travel times. The most impactful restrictions and closures were limited to weekends and overnight hours when traffic volumes were lowest. Decisions on when and where to allow restrictions and closures were based on real-time traffic data. This helped the team more accurately predict impacts of restrictions on the community. The data provided credible justification for allowing nontraditional start and end times to closures and restrictions. Every hour gained in the work zone allowed crews to complete critical work faster and more efficiently, reducing impacts on commuters and businesses.
After each major closure, the team held post-closure meetings between project team members and stakeholders. These open discussions allowed the team to review traffic data, talk about lessons learned and improve future operations. They created a continuous improvement loop of feedback that helped refine detour routes, signage and public messaging.
Coordination with ADOT’s stakeholders did not end there. Widening the freeway required the reconstruction of several interchanges. ADOT collaborated with its partners in the cities of Phoenix, Tempe and the Town of Guadalupe to coordinate longterm ramp and cross-street closures. These closures, lasting an average of 45 to 60 days each, allowed the developer to reconstruct the ramps more efficiently.
The construction team also used newly constructed CD roads as temporary travel lanes during various construction stages. This approach allowed the team to maintain capacity even as mainline lanes were reconstructed. The CD roads ultimately became a permanent feature, separating local versus regional traffic through the area, significantly reducing congestion and weaving.
Nonstop communication to the public and stakeholders
From the outset, ADOT prioritized transparency and timely information. Working with stakeholders, the team developed a communications strategy that blended traditional communications tools, such as emails, websites, flyers and canvassing. They also utilized nontraditional, innovative outreach tactics, including social media, a dedicated project mobile app and paid advertising campaigns.
The team used its connections to Phoenix’s local media outlets to amplify the reach of project messaging through press releases, onsite interview opportunities and behind-thescenes videos. These provided a candid look at construction progress. Additionally, social media became a powerful tool for real-time updates, safety reminders and milestone celebrations.
Educational campaigns targeted work zone safety, explained construction milestones and provided guidance on navigating the new CD road configuration. Such efforts helped maintain public support and encourage safe driving behavior throughout the work zone.
Partnering for success and working across jurisdictions
The Phoenix metropolitan region has prided itself with having strong partnerships across many jurisdictions. And this project’s success underscored the strength of ADOT’s collaboration with local governments, regional agencies and federal partners. ADOT worked closely with the cities of Tempe, Phoenix, Chandler, the Town of Guadalupe, the Federal Highway Administration and Valley Metro. Regular coordination meetings ensured that local priorities were addressed and that detour routes and traffic management plans aligned with community needs.
A vital partnership was with the Maricopa Association of Governments (MAG), which funded arterial roadway signal upgrades along key corridors adjacent to the project. These upgrades kept surface street traffic moving during freeway closures, minimizing delays for drivers. MAG also supported a paid advertising campaign that reached millions, ensuring that information about closures, detours and project benefits was widely disseminated.
Nearly four years after breaking ground on the I-10 Broadway Curve Improvement Project, the benefits are now realized. Since the project’s completion in June 2025, drivers are applauding improved traffic flow and safer crossings for pedestrians and cyclists. This corridor is now ready to support the region’s anticipated 25 percent population growth over the next 15 years. The project exemplifies what can be achieved through innovative delivery, strategic phasing and relentless communication.