Diverging Diamond Construction Starts This Week

January 16, 2012

Construction on the new “diverging diamond” interchange at Ashford Dunwoody Road and Interstate 285 is scheduled to begin this week. Click here, here, and here for more information on the design of the new interchange. Construction is anticipated to be completed in September.

When done, you’ll be driving on the wrong side of the road. No kidding. The new design is touted to improve traffic flow at the interchange.


Diverging Diamond in Motion

September 19, 2010

A couple of months ago, I reported to you (click for article) that the Perimeter Community Improvement District (PCID) is receiving a grant and a loan from the state infrastructure bank to construct a “diverging diamond” interchange at the junction of Ashford Dunwoody Road and I-285. Construction is anticipated to begin in 2011.

Below is a video of one of these interchanges. I found it to be a helpful way to see a “diverging diamond” in action. Credit goes to the Dunwoody Talk blog for finding this video.


What’s a Diverging Diamond?

July 10, 2010

Approximately a week ago I was notified by the Governor’s Office that the Perimeter Community Improvement District (CID) will be receiving a grant of $800,000 and a loan of $684,000 from the state infrastructure bank to construct a “diverging diamond” interchange at the junction of Ashford Dunwoody Road and I-285. The project will span as far south as the Ashford Green building and as far north as Perimeter Mall.

This begged the question: What is a diverging diamond interchange?

The answer: It’s an unusual interchange design where the traffic on the non-highway road (Ashford Dunwoody) drives on the opposite side of the road (the left-hand side) as it passes over the highway. It appears that this design will greatly improve traffic flow over I-285 and will be a remarkable improvement over the current layout.

Dunwoody City Councilman John Heneghan has posted more information on his blog, and there is a good article about the redesign in the Dunwoody Crier (click for links). You can find diagrams of the new layout in both places.

Construction is anticipated to begin in 2011.


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