Once deemed too expensive to build, Georgia’s largest infrastructure project has finally entered the construction phase with the April 22 groundbreaking for the SR 400 Express Lanes project.
Totaling $10.8 billion, the public-private partnership between the Georgia Department of Transportation (GDOT), the State Road and Tollway Authority (SRTA) and the SR 400 consortium Peach Partners, LLC will add dynamically priced, barrier-separated express lanes in both directions along a 16-mile stretch of one of Atlanta’s busiest corridors. Scheduled for completion in 2031, the project includes the construction of three new stations for the city’s planned bus rapid transit system.
SR 400 Peach Partners is a consortium of ACS Infraestructura, Meridiam, Acciona Concesiones, Acciona Construction, Dragados and Parsons. Along with completing the estimated $4.6 billion design and construction phase, SR 400 Peach Partners will finance, operate and maintain the new express lanes for 55 years.
Long envisioned as a means to relieve congestion in fast-growing north Atlanta suburbs, the SR 400 Express Lanes project was derailed in 2021 when GDOT rejected the only response bid to its original P3 procurement, which used an availability payment model, to exceed the state’s budget allocation. By then, the project had already been shelved two years into GDOT’s Major Mobility Investment Program improvements.
The agency’s relaunched search for a P3 partner included tailoring the acquisition to an income risk model, leading to the selection of SR 400 Peach Partners for the project in August 2024. The financing package, finalized last year, includes a TIFIA loan of nearly $3.9 billion, the largest loan ever to a single borrower.
GDOT says significant construction activities are underway in Fulton and Forsyth counties, including site mobilization, geotechnical survey and work, utility coordination, clearing and grading operations, traffic facility maintenance, and foundation work for structures and retaining systems. Georgia DOT Project Manager Beau Quarles says keeping traffic moving along one of Atlanta’s busiest corridors will be a key challenge during the six-year construction.
“Additional complexity includes rebuilding heavily traveled interchanges, coordinating utility relocations across multiple jurisdictions, and maintaining safe and reliable access for surrounding communities and businesses,” adds Quarles.
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To address these challenges, GDOT says the project is being delivered through a phased construction approach that prioritizes maintaining roadway capacity, incorporates off-peak and overnight work when feasible, and sequences improvements to minimize disruption. The project team will also use a combination of rigid and flexible pavement strategies tailored by corridor segment, along with increased use of precast elements to speed installation, improve quality control and reduce impacts to live traffic by enabling parallel fabrication and installation.
Other innovative design and construction strategies identified by SR 400 Peach Partners include the use of start-up construction packages to reduce overall design and construction duration, the use of straddle bent steel caps for rapid erection during overnight lane closures, and completion of planned culvert rehabilitation techniques to reduce traffic impacts.
