A GDOT rendering of the proposed roundabouts on Riverside Drive.

If Sandy Springs city officials decide not to go forward with a roundabout on the Riverside Drive/I-285 interchange, the city will be on the hook to spend $1.5 million to construct turning lanes on the intersection ramps.

The Georgia Department of Transportation first proposed the roundabout in 2011 after the city requested a new traffic signal at the interchange.

If a roundabout is constructed, the project will be funded with federal help at no cost to the city, except for landscaping and decorative street lights, state officials say. But if it’s not built, the city will have to pay to construct turning lanes on the ramps at a cost of $1.5 million.

Scott Zehngraff, assistant state traffic engineer for GDOT, told members of Sandy Springs City Council on July 15 that without the roundabout “the city is then . . . responsible for adding the turning lanes at the intersection.”

“It’s a commitment that you guys already made when you requested the signal,” he said. “So, when we approved the traffic signal, it was contingent upon the turning lanes being added.”

Zehngraff said the GDOT review was triggered by the city’s request for a traffic light at the intersection.

“Our policy requires whenever traffic signals are requested, we need to consider the roundabouts for safety reasons,” he said. “A roundabout drastically reduces the severity of crashes. It also reduces the number of crashes. The reason is that as two roads intersect each other you have 32 potential conflict points, which a roundabout reduces to eight.”

Following a public workshop on the proposal in March, some residents in the Riverside area protested the potential roundabouts. The Riverside Homeowners Association sent a letter to GDOT and city council members expressing concerns.

Reed Haggard, president of the Riverside HOA, which represents some 700 homes, told Reporter Newspapers in May that even if the roundabouts alleviated traffic flow, the traffic would flow onto an already-congested Riverside Drive.

GDOT cited a higher-than-statewide-average of crashes at the Riverside intersection as part of its decision to explore roundabouts. Zehngraff said the roundabouts are considered a safety improvement, not an operational improvement.

“What is unusual about the ramps on Riverside?” asked Councilman Graham McDonald, who represents the Riverside area.

“You don’t have turn lanes, which the intersection needs if signalized,” Zehngraff replied.

“Has any study been done on Georgia drivers’ ability to navigate roundabouts?” Councilman Ken Dishman asked.

“Design has a lot to do with it,” Zehngraff said. “This works because it’s a single-lane roundabout.”

Councilmembers have also raised concerns that the roundabout study came about before the Braves announced the baseball team was moving to nearby Cobb County.

But Marlo Clowers, a project manager with GDOT, told the council that the Braves traffic wouldn’t overwhelm the roundabouts.

“There will possibly be some additional traffic south on Riverside to west I-285, but that’s not the most direct route to the stadium,” she said. “We don’t expect that delay would be significantly different with a roundabout than with any other project.”

McDonald points out that GDOT says the roundabout is not a permanent fix. He added that most of his District 3 constituents that he’s heard from are against the project.

“I think a permanent solution that solves safety issues needs to be the focus, not a limited one that’s on the freeway and not on neighborhood streets,” he said. “I do continue to have concerns as the plans currently stand. [A roundabout] may cause safety problems by increasing the volume of traffic on Riverside and contributing to cut-through traffic.”

Ann Marie Quill

Ann Marie Quill is Associate Editor at Reporter Newspapers.

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