The full 30-mile project is expected to cost $834 million. BOB ANDRES / BANDRES@AJC.COM
Photo: Bob Andres
Photo: Bob Andres

Giant toll lane project ramps up — and up — on I-75 and I-575 in Cobb and Cherokee

30 miles of reversible lanes, with 39 new bridges

The next solution to Atlanta’s traffic is rising on massive columns of concrete and steel that march along Interstates 75 and 575 in Cobb and Cherokee counties.

The Northwest Corridor toll lane project is monumental in every way.

The project is remarkable not only for its 39 bridges: one of them, at 10 stories, is taller even than Spaghetti Junction, while another is 6,000 feet long; or its $834 million price tag; or the fact that this single endeavor is 30 miles long; or even for the slightly unsettling idea that the lanes will reverse direction twice per weekday: going inbound in the morning, shutting down near midday, flowing outbound in the evening.

Overriding all that is this: the Northwest Corridor express toll lanes represent the state’s primary strategy for fixing interstate traffic jams around metro Atlanta. The idea is simple: relieve congestion by billing the people who cause it.

By 2018, there will be more than 50 new miles of express toll lanes running through the median of I-75 south of metro Atlanta, towering above the west side of I-75 and I-575 northwest of the city, and adjacent to I-85 all the way up to the Hamilton Mill Road exit in Buford. Those are in addition t0 the 16 miles of High Occupancy Toll (HOT) lanes already operating on I-85 in Gwinnett County.

At the project’s groundbreaking, Gov. Nathan Deal called it “the most impactful and important project we’ve done here in decades.”

Metro toll-lane network envisioned

The Northwest Corridor project opens a new era in metro Atlanta’s decades-long battle with traffic: it’s huge, it’s expensive, and it’s just the beginning. Several years ago, state transportation officials decided that they would add no new lanes to metro Atlanta interstates unless the lanes were tolled.

By 2040 and perhaps far sooner, express toll lanes won’t be confined to portions of I-75 and I-85. You’ll find them along Ga. 400 and the top end of I-285, too. Eventually the plan is to connect all the major interstates around Atlanta with a seamless network of optional toll lanes.

Currently one-third of all the money budgeted for adding new lanes to arterial roads and interstates in the region through 2040 is earmarked for them. The infusion of a billion dollars annually in revenue from a recent gas tax hike and other new transportation-related fees could accelerate the timeline.

The first step toward that toll network are the Northwest Corridor and the I-75 South Metro Express Lanes. The I-75 South Metro project is a smaller-scale, 12-mile tollway being built in the median of the interstate where it runs through Henry and Clayton counties.

The two projects are the first toll lanes to be built from scratch in metro Atlanta in more than two decades. They will differ significantly from the granddaddy of Georgia toll roads, Ga. 400, whose toll gates were torn down last year after the state ended the 50-cent toll.

This time, like the I-85 HOT lane, there will be no expirati0n date. These toll lanes are here to stay.

‘It’s all going to come together’

The idea for the Northwest Corridor has been around since at least 2004.

The I-75/I-575 corridor is one of the most congested in the state, carrying traffic between commercial centers at Town Center, Kennesaw State University, Marietta and Smyrna.

The project as currently conceived several earlier concepts fell through — has been in the works since 2012. Nevertheless, many people didn’t realize that the Northwest Corridor was coming until the bulldozers arrived and shovels started turning earth.

The state Department of Transportation acknowledges this and is planning to step up public education efforts as the toll lanes near their opening date.

“I think it’s a disconnect between hearing stuff and the actual visual of seeing something on the road,” said Jill Goldberg, who has been appointed as GDOT’s “toll lanes ambassador.” “That’s when they go, ‘Look at this, it’s huge!’”

Because of its complexity and scope, the Northwest Corridor can be somewhat difficult to envision.

Phyllis Silverman left a recent Kiwanis Club meeting at West Cobb Senior Center with only a hazy understanding of how it will work, even after hearing the project manager’s 10-minute presentation.

“It’s very interesting, but I wasn’t able to follow it well,” Silverman said. “The entrances and the exits and the going south and the flyovers. After a while, it really was very confusing. I think it’s going to take the public a while to catch on.”

Goldberg often gets inquiries from people who think it’s three or four projects, rather than one long, 30-mile stretch of toll lanes that fork at the divergence of I-75 and I-575.

“We don’t usually do a project that is 30 miles long, especially in metro Atlanta,” Goldberg said. “They don’t realize it is different segments of one project and it’s all going to come together.”

Nuts and bolts of a monster project

So what is the Northwest Corridor?

On I-75 from Akers Mill Road up to the I-575 split, two toll lanes are being built along the west side of the freeway. More than five miles of the lanes will have to be elevated so that they soar above existing development and highway interchanges, said John Hancock, project manager for GDOT.

The project’s 39 bridges will feature 241 bridge columns and 219 spans, as well as 63 retaining walls and 45 sound barrier walls. The toll lanes will leapfrog an intersection here and duck beneath an interchange bridge there as they progress toward the Perimeter. The one thing they won’t do is tunnel underground.

The tallest of the bridges will arch 105 feet above ground level. That’s 15 feet higher than the tallest bridge at Spaghetti Junction. The Canton Road Connector bridge to the north will be about six stories above ground level.

If you’ve ever driven — or more likely crawled through — the I-285/I-75 “Cobb Cloverleaf,” you might like the idea of rising above that contemptible interchange on the tallest highway bridge in the state. That 10-story flyover is one of three new flyovers that will be added to the existing scheme.

David Welden, president of Lost Mountain Kiwanis club and member of a citizen committee looking at adding toll lanes along I-285, said the project is an engineering marvel.

“All the way around it’s just been a smart project,” said Welden. “I think it’s an exquisite design. The best improvement in traffic flow in the history of Atlanta.”

Novel as the concept may be to Atlanta, it’s not a particularly remarkable project in the United States. Ginger Goodin, the policy center director for Texas Transportation Institute, said there are similar “mega projects” involving multiple tolled lanes in Dallas and Houston that each cost more than $1 billion. And the first reversible tollway was built in San Diego in the late 1990s.

The most expensive project, for now

Transit buses and registered vanpools will be able to use the lane without paying the toll. But unlike the I-85 HOT lane, three-plus person carpools cannot.

Drivers will access the toll lanes via six brand-new I-75 interchanges.

They will be at I-285, Terrell Mill Road, Roswell Road, I-575, Big Shanty Road and Hickory Grove Road.

Farther north beyond the I-75/I-575 split, three slip-ramps on I-575 will enable drivers on the non-tolled highway to “slip” over into the toll lane through a break in the concrete barrier.

At the time it was approved, the $834 million Northwest Corridor was the most expensive road project in state history. It will soon be eclipsed by the $1-billion-plus redesign of the I-285/ Ga. 400 interchange.

The project is being built through a public-private partnership with Northwest Express Roadbuilders — a joint venture between Archer Western Contractors and Hubbard Construction Co. The partners will design and build the lanes and provide 10 percent of the funding, to be repaid by the state when the road opens.

Georgia DOT and the State Road and Tollway Authority will maintain and operate the lanes.

NEXT WEEK: State transportation planners are gambling a billion dollars-plus that drivers fed up with traffic will be willing to use a network of toll lanes planned for metro Atlanta. But are Atlantans ready to embrace toll lanes?

Support real journalism. Support local journalism. Subscribe to The Atlanta Journal-Constitution today. See offers.

Your subscription to the Atlanta Journal-Constitution funds in-depth reporting and investigations that keep you informed. Thank you for supporting real journalism.