
Since June, motorists who travel along the Ashford Dunwoody Road interchange at I-285 have driven through Georgia’s first Diverging Diamond Interchange.
On Nov. 16, Lt. Gov. Casey Cagle along with Dunwoody Mayor Mike Davis, and representatives from the Perimeter Community Improvement Districts (PCIDs) and the Georgia Department of Transportation (GDOT) dedicated the interchange.
The $6 million Diverging Diamond Interchange was initiated in 2009 by the PCIDs to improve the 40 year old interchange.
The Diverging Diamond Interchange design, which originated in France, shifts the flow of traffic to the opposite side of the road to reduce points of traffic conflict and improve traffic flow and safety. Under normal free-flowing traffic conditions on surrounding highways, traffic delays are expected to be reduced by 15 to 20 percent during evening rush hours.
Traffic studies are now underway to determine the impact. PCIDs officials said results should be available by next summer.

“This innovative project is a testament to the drive and dedication of the Perimeter Community Improvement Districts to improve traffic congestion in the important Perimeter market and to the Georgia Department of Transportation for being receptive to creative, low cost ideas to meet traffic challenges,” Cagle said. “The economic health of the Perimeter market is important not only to the businesses and cities located in this area, but also to local and state government that depend on the tax revenues generated in the Perimeter area.”
The PCIDs initiated the Diverging Diamond Interchange project and secured more than $1 million funding for the engineering and project design. GDOT funded the $4.6 million cost of construction which began in mid-January interchange re-opened to crossover traffic June 3.
Recent work has included final paving and completion of crosswalks and a protected pedestrian median on the bridge.
Davis said that he is excited about Dunwoody being the showcase for Georgia’s first Diverging Diamond Interchange.
This is working better than what some expected,” he said. “It’s not only bringing traffic relief and safety to this major entry way into the city of Dunwoody, but it’s also helping to brand Dunwoody as a great place to live, work and play.”
DeKalb PCID Vice-Chair Kay Younglong, a senior vice president of Jones Land LaSalle, who has leased office buildings in the Perimeter market, said the Diverging Diamond Interchange helps continue the transformation of Perimeter community from a traffic-clogged market into sustainable model community.
“Companies want to locate and expand in a centralized area with good transportation infrastructure that provides access and connectivity,” Younglove said. “Improvements like the Diverging Diamond Interchange continue to make Perimeter and obvious choice.”