Construction on the $11 billion SR 400 Express Lanes project began April 22 along 16 miles of GA-400 between the North Springs MARTA Station and McFarland Parkway, and Alpharetta and Milton drivers will share the corridor with active work zones through 2031.
The Georgia Department of Transportation says most lane-impacting work will happen overnight, between 9 p.m. and 5 a.m., to limit daytime disruptions. No construction will take place on holidays.
Motorists should expect to see equipment mobilizing, phased traffic shifts, and new bridge construction along the corridor, according to GDOT. The department says it will provide advance notice of lane closures through local media, social media, road signage, and subscriber alerts at 400expresslanes.com.
What's being built
The project adds two tolled express lanes in each direction from North Springs to McGinnis Ferry Road, and one express lane in each direction from McGinnis Ferry Road to McFarland Parkway. Unlike the reversible express lanes on I-75, these lanes will run in both directions around the clock, according to a summary of the GNFCC 400 Insider podcast episode published July 16 featuring project leaders Kristin Winzeler of True North 400, Ann Hanlon of the Perimeter Community Improvement Districts, and Javier Gutiérrez Villanueva, CEO of SR 400 Peach Partners.
GDOT projects that, once complete, express lane users could save up to 17 minutes per trip during peak hours, with travel speeds up to 30 percent faster than general-purpose lanes.
Tolls will be dynamic, adjusting in real time based on traffic conditions through the Peach Pass system. Freight vehicles and trailers are not permitted in the express lanes. Access points will be more frequent than on some other metro Atlanta express lane corridors, according to the podcast summary.
Emergency vehicle access
Registered law enforcement and emergency vehicles will be exempt from tolls, according to GDOT, though all vehicles must carry a Peach Pass transponder registered with the State Road and Tollway Authority. Transit buses and registered vanpools will also ride toll-free.
Transit stations coming to Alpharetta
The project includes dedicated stations for MARTA's future Bus Rapid Transit system on GA-400. BRT service will begin at North Springs MARTA Station, with stops at Holcomb Bridge Road, North Point Mall, and Windward Park and Ride in Alpharetta, according to GDOT.
True North 400, the commercial improvement district serving portions of Alpharetta, Milton, and Roswell along the corridor, secured a $2 million grant from the Atlanta-Region Transit Link Authority in December 2025 to plan first-and-last-mile connections to those future stations. Winzeler called the grant a step toward connecting North Fulton residents to future BRT stations.
The bigger picture
The project is structured as a 56-year public-private partnership. SR 400 Peach Partners is responsible for design, construction, operations, and maintenance through approximately 2081. The consortium paid a $3.8 billion concession fee to GDOT at financial close in August 2025.
Nearly 300 business and community stakeholders attended the April 22 groundbreaking, according to True North 400.
GDOT also opened a new Exit 11A at McGinnis Ferry Road near Milton's Deerfield area as part of broader GA-400 corridor work. The $66 million interchange gives drivers another way on and off the highway without using Windward Parkway.
Residents seeking construction updates or wanting to report concerns can visit 400expresslanes.com, email [email protected], or call the project hotline at 770-209-2520.
