Faye DiMassimo
Director
Directors' Page1890 County Services Pkwy
Marietta, GA 30008
cobbdot@cobbcounty.org
(770) 528-1600
Department of Transportation
Diverging Diamond Interchange at Wade Green
GDOT will assist Cobb County to construct a diverging diamond interchange at Interstate 75 and Wade Green Road.
A diverging diamond interchange (DDI) is an innovative intersection traffic solution designed to increase capacity, decrease congestion, and minimize cost. The DDI is designed to ease the flow of heavy traffic by eliminating a left turn signal, and allowing two-directions of traffic to cross the opposite side of the side or cross street at or near the bridge point over the freeway.
Cobb County will be responsible for completing and funding the preliminary engineering and right-of-way costs for the project. Once completed, GDOT will fund up to $1 million of construction costs from their operational improvement lump sum. The rest of the $1.625 million cost will come from Cobb County SPLOST funds.
For a DDI, traffic on the side street is moved to the opposite side of the road at or near the intersections with the on and off ramps. This ‘cross-over’ occurs at a simple, two-way signal with no left turns which reduces conflict points. Because the DDI does not have left turns that must clear opposing traffic, the design can improve traffic movement with more green signal time for the side street. Traffic will move faster and safety is increased, resulting in less congestion and fewer crashes.
A diverging diamond interchange (DDI) is an innovative intersection traffic solution designed to increase capacity, decrease congestion, and minimize cost. The DDI is designed to ease the flow of heavy traffic by eliminating a left turn signal, and allowing two-directions of traffic to cross the opposite side of the side or cross street at or near the bridge point over the freeway.
Cobb County will be responsible for completing and funding the preliminary engineering and right-of-way costs for the project. Once completed, GDOT will fund up to $1 million of construction costs from their operational improvement lump sum. The rest of the $1.625 million cost will come from Cobb County SPLOST funds.
For a DDI, traffic on the side street is moved to the opposite side of the road at or near the intersections with the on and off ramps. This ‘cross-over’ occurs at a simple, two-way signal with no left turns which reduces conflict points. Because the DDI does not have left turns that must clear opposing traffic, the design can improve traffic movement with more green signal time for the side street. Traffic will move faster and safety is increased, resulting in less congestion and fewer crashes.
 DDI White Paper .gif){kind=small} DDI Location Map |
DDI Design In the News - MDJ Article from July 16, 2012 |
