Why Are They Cutting Down All the Trees Along GA 400 in North Fulton and South Forsyth?

If GA 400 suddenly looks completely different, you’re not imagining it.

Drivers through Roswell, Alpharetta and South Forsyth have watched huge stretches of the tree line disappear along GA 400.

Areas that were hidden behind dense vegetation are suddenly wide open. Construction equipment is appearing. Dirt is moving. And it’s creating an obvious question:

Where did all the trees go?

A major reason is the SR 400 Express Lanes project, which is now under construction along approximately 16 miles of GA 400 from the North Springs MARTA station through North Fulton and into South Forsyth.

And what you’re seeing now is only the beginning.

What exactly are they building?

The Georgia Department of Transportation is adding approximately 16 miles of optional, dynamically tolled express lanes along GA 400.

From the North Springs MARTA station to McGinnis Ferry Road, the project calls for two express lanes in each direction.

North of McGinnis Ferry, that changes to one express lane in each direction, continuing into South Forsyth to approximately 0.9 miles north of McFarland Parkway.

The existing general-purpose lanes remain available.

GDOT currently anticipates the express lanes opening in 2031.

Why does adding lanes require removing so many trees?

This is where the scale of what drivers are seeing starts to make more sense.

This isn’t simply a matter of cutting down a narrow strip of trees and laying another lane of asphalt beside the highway.

Construction involves a much larger physical footprint that can include new express lanes, access points, bridges and ramps, grading, drainage infrastructure, utility relocation, retaining structures and temporary construction areas.

GDOT’s construction updates have documented clearing and grubbing at multiple locations along the corridor as construction has progressed.

This project will change how GA 400 works

The express lanes will be optional toll lanes, not replacements for the existing general-purpose lanes.

Pricing will be dynamic, meaning tolls can change based on traffic conditions and demand.

The corridor is also being designed to accommodate Express Lanes Transit, including bus service using the managed lanes.

GDOT projects that the express lanes could provide travel times up to 30% faster than the general-purpose lanes during peak periods and reduce more than 19,000 hours of commuter delay per day across the corridor.

Those are project forecasts, not guaranteed individual travel times.

Why is all of this suddenly so noticeable?

Planning for the express lanes has been underway for years.

But 2026 is different.

The project has moved into active construction.

The formal groundbreaking occurred in April, and construction activity is now occurring at multiple locations along the corridor.

That’s why drivers are suddenly seeing areas that have looked essentially the same for decades change in a matter of months.

Alpharetta is going to look very different

Some of the most noticeable changes are occurring through the heart of North Fulton.

The project runs through the Mansell Road, Encore Parkway/North Point, Old Milton Parkway/Haynes Bridge and Windward Parkway areas before continuing north toward McGinnis Ferry.

And the conceptual renderings show just how significant some of these changes could be.

And South Forsyth is part of this story too

The project doesn’t stop at the Fulton County line.

It continues through the McGinnis Ferry area and north toward McFarland Parkway.

There is also separate transportation construction around McGinnis Ferry, including the new interchange at GA 400.

That means not every construction site or tree-clearing area visible from GA 400 necessarily belongs to the Express Lanes project.

What happens next?

Expect the transformation to become more visible before it becomes less visible.

Tree clearing and early site preparation lead into grading, utility relocation, drainage work, retaining structures, bridge work, roadway construction and eventually new express-lane infrastructure.

The current target for opening the system is 2031.

In other words, the missing trees aren’t the finished project.

They’re one of the first highly visible signs of a construction program that will reshape GA 400 for years.

But there’s one section I wanted to understand better

While researching the larger project, I started looking closely at the actual engineering plans around Mansell Road and Haynes Bridge Road.

And that’s where this story gets much more local.

That section sits near Big Creek, the Big Creek Greenway, Haynes Bridge Middle School and established residential areas, and the actual plans tell a much more complicated story than simply “they’re adding express lanes.”

That’s the next story I’m working on.

We’ll look at what is actually planned between Mansell and Haynes Bridge, why the Big Creek corridor matters, where the new infrastructure is expected to go, and what is approved versus what remains subject to final design.

Follow BrokerBroDad News for that breakdown. If the GA 400 changes are part of a move decision for you, start with the North Atlanta Buyer Guide and the Georgia Relocation Guide.