In Atlanta there’s no such thing as typical when it comes to DOT projects, but if there’s a model to take a hint or two from, it’s the work going on restructuring the I-20/Fairburn Road interchange.
“There’s nothing standard about anything in Atlanta. Every [project] is a challenge, and every one is different,” said Georgia Department of Transportation Project Engineer Mickey McGee.
In the formerly rural Douglas County population has bloomed — and so has congestion. The $26.8 million contract Snellville’s E.R. Snell took two years ago reads like a standard interstate interchange reconstruction: just under 1 mi. (1.6 km) of roadway reconstruction, interchange improvements including video detection systems and construction of a new bridge over I-20.
“It’s reconstruction of the roadway interchange, improvements including the installation of video detection systems on State Road 92 [Fairburn Road] and including the construction of a bridge and approaches over I-20, and widening that bridge to give it more turning capacity,” GDOT spokesman Mark McKinnon said. “It’s going to dual turn lanes in both directions to enter the interstate and it’s also going to be a longer bridge in order to accommodate future HOV [High Occupancy Vehicle] lanes.”
That’s key, McGee said.
All around Atlanta, interchanges have been widened to accommodate future traffic flow tool improvements including HOV lanes, and the trend isn’t likely to abate any time soon.
“As we review interchanges, and there’s one to the east of this one we’ll probably consider next year, we try to look at what the future transportation plans we have in store call for, and one of the parts of that is including HOV lanes in I-20,” McGee said. “In order to accommodate that, the existing overpasses have to be widened. This interchange also has been identified as not working well, so basing our reviews on that would have moved it up the list as far as being replaced and having reconstruction. The two variables make the project more viable.”
McGee said the construction reflects the needs expressed by most interchanges around the city.
“I think the reconstruction at this interchange has several points: No. 1 that the existing bridge needed to be wider to accommodate the future HOV lanes, and No. 2 that this is a congested area and there are not enough lanes to handle the capacity of the traffic from the roadways on the bridge,” McGee said. “The one we’re building is twice the size of the one we’ve removed, in the number of lanes and also accommodating the turn lanes. The turn lanes on the existing bridge were short and narrow and these turn lanes we’re building on the new bridge are dual lanes in each direction. It’s a tremendous amount of improvement.”
Also ubiquitous in GDOT planning is the installation of video monitoring systems. McKinnon explained that the system is another step the state is taking to improve traffic flow.
“Those are being tied into our center for traffic monitoring,” McKinnon said. “All the cameras are strictly monitoring traffic, and we can also use the cameras for signalization sometimes instead of putting the traffic loop in the ground. We’re using the video detection to cycle the systems, though that’s not the case here at SR 92.”
Another thing that typifies interchange bridge replacement these days for GDOT is contractor discretion. For this job, Snell had the option to build the bridge half at a time by closing lanes or to find a different solution.
“This one is unique because we’re actually building a detour bridge and shifting traffic onto that detour bridge in its entirety so that we could remove the old bridge all at one time and build the new one all at one time,” McGee said. “A lot of times what we have to do is shift traffic and lose a couple of lanes and build half the bridge and shift the traffic and build the other half, but because the company can construct a detour bridge it saves on costs and also saves construction time. Once the new bridge is finished we can put the traffic on it then tear out the temporary bridge.”
In one of the most rapidly growing urban centers in the country interchange reconstruction like the one at I-20 and Fairburn Road will be common in the future.
“I’d say that 90 percent of the interchanges in Atlanta, other than the ones that we’ve reconstructed in the last 10 years, will be built wider to accommodate future managed lanes,” McGee said. “There are plans on other interchanges. I’ve seen preliminary plans that may or may not move forward, and we do have one project that’s just begun on the south side at State Road 54 and I-75 that’s kind of similar to this one —widening the bridge out and replacing the bridge and making it a little wider for managed lanes there.”
McGee added that GDOT is seeing work on two other interchanges nearing completion. That should make commuters in Atlanta happy.
“I’ll be candid,” he laughed, “I’m not sure that there’s a whole lot of folks in this city that appreciate any of our work until we get through with it. There’s a lot of fussing and arguing and pointing of fingers when the building is happening, but once it’s done, you don’t hear that anymore because it’s done.”
Work is scheduled for completion in winter of 2010. McGee said that future projects are still under consideration by GDOT, which is currently reacting to budget constraints by prioritizing projects.
“Upper management is going through it with a fine-toothed comb,” McGee said. “They’re looking at every project.” CEG
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