State Route 400 Express Lanes

Georgia’s State Route 400 is a heavily traveled north-south corridor, serving the fastest growing communities in the metro Atlanta region, with traffic volumes expected to significantly increase to over 360,000 daily commuters by 2046. The Georgia Department of Transportation (Georgia DOT) aims to enhance mobility along the SR 400 corridor by adding express lanes in each direction between the North Springs MARTA Station and McFarland Parkway. These express lanes will be dynamically tolled, providing a mobility option for drivers who choose to pay to use them and free for transit vehicles operating in the corridor. All of the existing non-tolled general purpose lanes will remain available to drivers at no charge.

The new express lanes are a key component of Georgia DOT’s Major Mobility Investment Program, a group of projects aimed at reducing congestion and enhancing safety along Georgia's key freight and passenger corridors. Spanning approximately 16 miles, the new SR 400 Express Lanes are designed to:

• Improve mobility and provide reliable travel times for express lane drivers and transit users
• Enhance access to existing transit and support new bus rapid transit (BRT) operations in the corridor with the construction of two BRT stations
• Improve the level of service throughout the entire corridor, including reduced congestion for general purpose lanes
• Offer seamless customer experience with the continued use of Peach Pass or other interoperable toll transponders as toll collection device

Using a Public-Private Partnership

Georgia DOT is using a public-private partnership (P3) revenue risk model, in which a private partner will design, build, finance, operate, maintain and toll the project for 50 years following completion of construction. This approach allows the state to improve the region’s mobility while reducing public funding, ensuring reliable travel times, offering new mobility options, supporting transit and driving innovation in design and operations.

In August 2024, the procurement process for SR 400 Express Lanes reached its conclusion with the award of the contract to the SR 400 Peach Partners. Their winning proposal offered to deliver the $4.6 billion project at no additional cost to the state and to make an upfront concession payment to the state of over $4 billion – an unprecedented outcome in the U.S. P3 transportation market.

Providing Program Support

HNTB serves as Georgia DOT’s program management consultant for the P3 Division, which oversees the Major Mobility Investment Program’s portfolio of projects. The firm also has provided executive owner’s representative services to help shape the P3 revenue risk model approach and commercial structure, coordinate with other advisors and conduct the procurement process for the SR 400 Express Lanes and for the express lanes planned on I-285.