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DOT hopes drivers take a shine to diverging diamond
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People attending the DOTs open house check out the proposed renovations to the Interstate 95/Highway 21 interchange. - photo by Photo by Paul Floeckher

State Rep. Bill Hitchens has seen the two “diverging diamond interchanges” in use on metro Atlanta highways.

While his opinion of the traffic design falls short of a ringing endorsement, Hitchens does consider it the best option to alleviate congestion and improve safety at the Interstate 95/Highway 21 junction in Port Wentworth.

“I think it’s certainly much better than what we have,” he said.

Hitchens shared his thoughts at an open house the Georgia Department of Transportation hosted last week at the Georgia Tech Savannah campus, to show the plans and answer questions about the proposed diverging diamond interchange at I-95’s exit 109.

Though the 95/21 interchange is in Chatham County, its future will impact significantly Effingham drivers who take  those roads regularly, particularly for work commutes.

“Everybody works in Savannah,” Hitchens said, “and I alter my schedule to the point where I try to make my meetings or whatever around the morning rush and the evening rush.”

Under the proposal, Highway 21 would be widened to four lanes in each direction in the interchange area. The additional lanes on 21 would end as a left-turn-only lane on Highway 30 to the north and right-turn-only lane at Hendley Road to the south.

“It’s a design that keeps everybody flowing, and then they just turn where they need to go,” said Jill Nagel, district communications officer for the DOT.

The northbound I-95 exit ramp onto Highway 21 would maintain a single right-turn lane and be widened to three lanes turning left toward Effingham County. The southbound I-95 exit ramp would not be modified.

To keep traffic moving, a diverging diamond has drivers use the left side of the road to travel through the interchange. Drivers are directed by signs and lighted signals.

Former state Rep. Ann Purcell, who now serves on the State Transportation Board, acknowledged being apprehensive the first time she rode through a diverging diamond interchange in Atlanta.

“I thought, ‘Oh, my gosh, I’m on the wrong side of the road — somebody’s going to hit me,’” she said. “But then I realized that it’s designated so carefully that motorists aren’t confused, even with their first time driving it.”

Purcell and Hitchens both emphasized that, along with easing traffic congestion and reducing drivers’ commute times, the 95/21 improvements would make the interchange safer. Traffic at exit 109 often backs up a mile or more on I-95 northbound.

“You get a tractor trailer running 70, 75 miles an hour that tops that hill and everything is stopped, he can’t stop,” Hitchens said. “The simple physics are that they weigh so much, they’re going to take longer to stop and they’re going to do a lot more damage.”

Nagel touted the diverging diamond interchange as more cost-effective than other options, such as one proposal to build a bridge over the interstate and continuing to Highway 30. That project would have cost $50 million, she said, compared to a little over $6.5 million for the DDI.

“When you’re talking about bridge construction, that’s a huge price tag,” Nagel said. “When you’re looking at doing something new and innovative that you’re just constructing more lanes of traffic, it’s a smaller price tag.”

Final approval would come from the Federal Highway Administration, Nagel said. Funding for the project is available, according to Purcell.

“I have tried to make sure that funding is there,” Purcell said. “We’re pushing very hard to make it a top priority, because it is a much-needed one.”

Work to the 95/21 interchange was one of the projects included in a proposed one-cent sales tax for transportation projects Georgians voted on in 2012. The 10-county region that includes Effingham shot down the T-SPLOST with 57 percent of the vote.

“I always remind people, if we’d passed T-SPLOST, we probably wouldn’t have this problem,” Hitchens said. “Truth of the matter is, this is funded and we don’t have any funding for anything else.”

Purcell agreed that a different plan for 95/21 likely would have emerged had T-SPLOST been passed, but added, “That’s beside the point. We’ve got to utilize the funding that we have to the best extent that we can stretch every dollar to get the best project that we can for the safety of folks in traveling.”

The DOT hopes to start renovating the interchange in the fall of 2015 and have construction completed in the first part of 2017, Nagel said.

Share your thoughts
The Georgia DOT is taking public comment through Aug. 26 regarding the proposed diverging diamond interchange at Interstate 95 and Highway 21.
Go to and click “Public Outreach.” Select “Effingham” on the county menu, select “8/12/14 PIOH for I95/SR21 DDI” and follow the instructions to comment.
Send comments to Hiral Patel, Georgia DOT, 600 West Peachtree St. 16th Floor, Atlanta, GA 30308.
All comments will be considered in the project design and must be received by Aug. 26.