It was a quiet Friday morning amid the empty cubicles in a Sandy Springs office building. But the tapestry-sized highway maps on the walls gave a hint of the work that will soon set the place buzzing for years to come.

The address is 270 Carpenter Drive, Suite 450, and the offices are the Georgia Department of Transportation’s command headquarters for the I-285/Ga. 400 interchange reconstruction project. The first dirt will be plowed for the “Transform 285/400” project within the next week, and work will continue into mid-2020.

“This is a big project and there’s a lot of eyes and ears on it,” says Butch Welch, the GDOT project manager, who will lead the 15 to 20 people in the headquarters keeping that attention as work ramps up.

That’s why GDOT chose to have a local headquarters in that building, which sits about 500 feet from I-285’s Roswell Road exit and less than a mile from the interchange. And three floors above them, an elevator ride away from any questions, is North Perimeter Contractors, the team of companies that won the $460 million project.

“We can get there fast, not worry about the traffic,” said GDOT communications manager Jill Goldberg.

“We try to be out there at least every day,” said Welch about reviewing the preparation work already underway along Ga. 400 in Sandy Springs. GDOT and private contractors assisting in the project’s oversight have the ability to view live traffic camera footage of the highways, but Welch said he is “one of the people who wants to get out in the field, whether it’s 2 in the morning or 2 in the afternoon.”

Welch and Goldberg spoke in a small, freshly painted conference room in the headquarters, which has yet to acquire lived-in touches.

Name placards for future staff members hang on vacant cubicles. A few pieces of art, including a painting of another mega-project, New York City’s Brooklyn Bridge, brighten a visitor waiting room. The most notable decorations are the scroll-like highway maps stretching for yards, depicting plans for such details as sound-blocking walls and new highway signs.

The maps also give a sense of the sheer scale of the massive project. Rebuilding one of the state’s busiest highway interchanges—it handles about 400,000 vehicles per day—to improve capacity and flow is just the beginning.

The work also involves adding “collector-distributor lanes”—physically separated exit and entrance lanes—to 400 north to Sandy Springs’ Spalding Drive and to 285 between Roswell Road and Ashford-Dunwoody Road in Dunwoody and Brookhaven.

The 400/Abernathy Road interchange in Sandy Springs will be rebuilt as a “diverging diamond,” in which traffic flow changes in time with traffic lights to move cars faster, and 33 bridges will be built or rehabbed.

“We’re getting ready to blow up the interchange,” Welch says cheerfully, adding it’s “not going to be as devastating as people think.” He cited two reasons: Most of the work will be done at night, and through a phased construction that allows all roadways to remain partly open during construction and, at least in theory, to improve traffic before the work is totally done. In fact, the new interchange is still being designed and its work may not begin for another year or more.

There was, naturally, a diagram hanging on the wall to illustrate the phasing. Welch sprang up to point out that it begins with reconstruction of the Mount Vernon Highway bridge over 400.

Sporting a silver crew cut and immaculate work shirt and jeans, Welch speaks about such complexities with an engineer’s precise details and notes of caution. Communicating such details to the public and local officials is another reason to have a local headquarters, which anyone is welcome to visit, Welch said.

“We can’t solve everybody’s problem. In fact, we’re probably going to create a lot of problems” in the short term, Welch said. But what GDOT can do is clearly communicate the plans and coordinate mitigations with whoever is affected. As a small example,

Welch cited the need to coordinate the project’s work so it won’t conflict with cities’ roadwork or right-of- way maintenance.

“With taxpayer dollars, we don’t want to be doing something and then tearing it up,” he said.

Meanwhile, Welch said, any construction pains will be worth it. “What you see out there now, that’s going to go away,” he said.

“You’ll be able to go”—he whistled and sliced a finger through the air—“straight through.”

To see details about “Transform 285/400,” go to the GDOT project website here.

Other ‘Transform 285/400’ updates

Current construction phasing

The current construction plan starts with replacing the Mount Vernon bridge, followed by, in order: new lanes on 400’s east side north of Hammond Drive; similar work on 400’s west side; the same work on Ga. 400 south of Hammond; the Abernathy diverging diamond; and finally the 285 and interchange work.

GDOT recently mailed out notices for two open houses about proposed sound-blocking walls along 400. Both will be held Feb. 9, 10 a.m. to 2 p.m. and 1 to 4 p.m. at Congregation B’Nai Torah, 700 Mount Vernon in Sandy Springs. Affected property owners get to vote on whether any sound barriers will be built.

Traffic coordination

The two cities directly impacted by work are Dunwoody and Sandy Springs. Their police departments are working on an agreement that will allow off-duty officers to work traffic details in both jurisdictions, Sandy Springs Police Chief Ken DeSimone told his City Council Jan. 17.

Another concern is the new Atlanta Braves stadium, set to open in March farther down 285 in Cobb County. The 285/400 night lane closures will start after game time, potentially surprising and confusing fans with new conditions on their way home. Goldberg said GDOT is working on a communications plan, possibly including messages on the giant screens in the stadium.

The next project

“Transform 285/400,” big as it is, is not the end of work in the area. GDOT already has preliminary plans to add “managed” lanes in the area within the next decade. Managed lanes mean some type of restricted-access lanes, usually by a toll. Goldberg said GDOT officials will present information about the managed lanes at the Sandy Springs City Council’s retreat Jan. 24 at Lost Corner Preserve.