A landmark public-private partnership highway project is now under active construction north of Atlanta. On April 22, 2026, the Georgia Department of Transportation and developer SR 400 Peach Partners broke ground on the State Route 400 Express Lanes — a 16-mile corridor expansion with a total project cost of approximately $11 billion and construction costs of $4.6 billion, making it one of the largest P3 demand-risk highway projects in U.S. history. Construction Dive and ACS Group confirmed the groundbreaking.

What Is Being Built

The project adds tolled express lanes in each direction along SR 400, one of the busiest commuter corridors in metro Atlanta. Specifically:

• Two tolled express lanes in each direction from the North Springs MARTA Station in Fulton County to McGinnis Ferry Road in Forsyth County (approximately 12 miles)
• One tolled express lane in each direction from McGinnis Ferry Road to McFarland Parkway — extending the corridor an additional 4 miles north

The construction team will also add new bridges, enhanced connections to the I-285/SR 400 Interchange, and corridor-wide Intelligent Transportation Systems (ITS) to manage dynamic tolling. Tolls will be dynamically priced using Georgia's existing Peach Pass system. The Metropolitan Atlanta Rapid Transit Authority (MARTA) will operate Bus Rapid Transit service within the express lanes between North Springs and Windward Parkway once the project opens. According to the official Georgia DOT SR 400 FAQ, travel in the express lanes is projected to be up to 30% faster than general-purpose lanes during peak times.

The P3 Structure and Financing

The project is structured as a full concession P3: SR 400 Peach Partners — a joint venture of ACS Infra, Acciona, and French asset manager Meridiam — will design, build, finance, operate, and maintain the corridor for approximately 50 years after the 2031 opening. At the end of that term, GDOT and the State Road and Tollway Authority (SRTA) resume control.

The $11 billion total financing breaks down as follows, per the official GDOT FAQ:

• TIFIA Loan (U.S. DOT): $3.9 billion (36%)
• Private Activity Bonds: $3.4 billion (31%)
• Developer Equity: $3.4 billion (32%)
• Georgia DOT contribution: $120 million (1%)

The developer made a $3.8 billion concession payment to Georgia DOT at financial close in August 2025 — meaning the state received an upfront cash payment in exchange for granting toll revenue rights. Per GDOT, no additional public funding is required to build, operate, or maintain the project. ACS Group confirmed the 5.5-year construction period and 50-year operations term in its April 21 announcement.

The Construction Team

FlatironDragados (Atlanta-based) and Acciona Construction (Madrid) are the joint venture builders executing the physical work. The project is part of Georgia's Major Mobility Investment Program (MMIP), designed to overhaul congested corridors using alternative delivery and P3 structures. Infrastructure firm Ferrovial completed a companion $690 million contract to upgrade the I-285/SR 400 Interchange in 2025, setting the stage for the express lanes construction. Acciona's official release confirmed construction began in spring 2026, with the express lanes targeted to open to traffic in 2031.

Why This Matters to Construction Professionals

The SR 400 project illustrates how the U.S. is increasingly financing its largest highway expansions — not through traditional federal-aid appropriations alone, but through complex P3 structures backed by TIFIA loans, private bonds, and long-term toll concessions. For civil contractors, this model rewards firms with the financial capacity and technical depth to compete for design-build-finance-operate-maintain packages. The trend is accelerating: Georgia has additional P3 projects planned under MMIP, including the I-285 Top End Express Lanes, and peer states are watching.

The project also signals strong demand for ITS and tolling systems specialists, structural bridge contractors, and corridor-wide earthworks teams. With a 5.5-year construction timeline extending to 2031, SR 400 will sustain demand across multiple construction seasons in the Atlanta market.

Implications for Owners, Developers, and Subcontractors

Property owners and commercial developers along the SR 400 corridor — running through Alpharetta, Roswell, and Sandy Springs — should note that improved travel times consistently drive commercial and mixed-use development near express lane corridors. Comparable projects in Virginia and Texas produced measurable development activity within two to three years of opening.

For subcontractors, FlatironDragados and Acciona Construction are major primes with active subcontracting programs. Construction will advance in phased segments, meaning bidding opportunities will emerge in waves through 2029. Georgia's DBE program requirements apply to federally funded portions of the work, and with the TIFIA loan covering over a third of total costs, federal compliance expectations are significant.

What to Watch Next

• I-285 Top End Express Lanes — GDOT's next MMIP project, which will eventually connect to SR 400's express network, is in procurement
• Construction staging and lane closure announcements through the SR 400 corridor will be issued as work advances through spring and summer 2026
• Revenue service in 2031 is the key milestone; schedule changes would affect subcontracting timelines
• Whether the $3.8 billion upfront concession payment model is replicated by other state DOTs considering similar structures will be closely tracked nationally

Bottom Line

The Georgia SR 400 Express Lanes project is a signal of where U.S. highway finance is heading. With an $11 billion total investment, a TIFIA loan exceeding $3.9 billion, and a 50-year toll concession backing the deal, this is P3 infrastructure finance operating at full scale. For the construction industry, it represents five-plus years of sustained activity in metro Atlanta — and a template that other states are already studying.

Sources:
Construction Dive — FlatironDragados, Acciona turn dirt on $4.6B P3 highway project
Georgia DOT — SR 400 Express Lanes FAQ (Official)
ACS Group — SR 400 Groundbreaking Announcement
Acciona — Construction begins on major Express Lanes project in Atlanta
Georgia Major Mobility Investment Program — SR 400 Project Page