University City

January 22, 2013

New projects to ease I-85 traffic

Among upcoming projects is a $98.6 million turbine interchange at intersection of I-485 and I-85, the first of its kind in North Carolina.

Interstate 485 isn’t the only highway getting fast-paced changes.

Crews are now working on projects surrounding Interstate 85 that involve the construction of more lanes, innovative interchanges and “super-streets.”

“We’re just so excited about these jobs,” said N.C. Department of Transportation spokeswoman Jen Thompson. “We’re spending money and getting started and doing things we’ve never done before.”

Among those projects is a turbine interchange at the intersection of I-485 and I-85. The interchange, which costs more than $98.6 million to build, will be the first of its kind in North Carolina.

“If we get it done on time, it’ll be the second in the nation,” said Davis Diggs, the project manager and a district engineer for N.C. DOT. He said he expects the interchange will be finished in August 2014.

The interchange, which will cover about 100 acres, will create a transition between the two highways that doesn’t involve having to slow down.

Diggs said the interchange is built for driving at 65 mph, but he doesn’t know what the posted speed limit will be.

“Everything in the interchange functions in a swirl,” he said. “There’s no stopping, no oncoming traffic.”

Diggs said that although the turbine interchange first became popular in Europe, drivers won’t get stuck going in circles like Clark Griswold did in “National Lampoon’s European Vacation.”

“Once you’re in it, you’re going to come out somewhere,” Diggs said.

The interchange involves the construction of 19 bridges, which Diggs said will be easy to maintain because of the way they’ll be laid out.

Thompson said the project has generated a lot of excitement.

“We’ve had other states asking about it, and the Federal Highway Administrator (Victor Mendez) came last year to see plans for it,” she said.

Beyond the turbine interchange, crews are also widening a 7.3-mile stretch of I-85 by two lanes in each direction.

The widening will begin south of Bruton Smith Boulevard (near Concord Mills) and ends just north of N.C. 73 (Davidson Highway). The project will cost more than $138.7 million, Diggs said.

Construction was delayed while waiting for environmental permits, but Diggs said he expects the lane additions to be complete by spring 2014. Two lanes should continue to be open throughout construction.

“You have just as many lanes before we started the work,” Diggs said.

Along that stretch of I-85, two intersecting roads, Poplar Tent Road and N.C. 73, will have innovative interchanges called diverging diamond interchanges and will also be made into what N.C. DOT calls “super-streets.” The cost for the interchanges and super-streets is about $11 million, said Thompson, and that project should be complete in June 2014.

The diverging diamond interchanges – the first of their kind in the state – will direct drivers to drive on the opposite side of the street, without oncoming traffic, to easily merge onto the correct road.

“It’s intuitive,” Diggs said. “If you want to turn right, stay in the right lane, and if you want to turn left, you stay in the left lane.”

Overall, N.C. DOT is saving about $50 million by building the interchanges, Diggs said. The projects are also employing more people, and Diggs has seen direct evidence of that. He said normally 20 people work in his office, but with the construction of these projects, 40 are now working there.

The construction for the two super-streets, Poplar Tent Road and N.C. 73, involves widening to improve traffic flow and prohibiting left turns.

“The signal will cycle faster,” Diggs said of stoplights.

On Poplar Tent Road, there will be a roundabout at the Gable Oaks subdivision, and the super-street will extend just past the Derita Road/Odell School Road intersection.

If drivers are headed west on Poplar Tent Road and want to turn left onto Derita Road, they will have to pass the intersection and enter what Diggs called a “U-turn bulb” to change directions on Poplar Tent Road. Then the driver can turn right on Derita Road.

“It keeps the traffic moving faster, and it’s safer,” Thompson said. “It eliminates a lot of left-angle traffic.”

Thompson said that N.C. DOT is planning to improve the next segment of I-85 and that she hopes the next project will be solidified this year.

“This corridor is so vital,” she said. “We definitely need to remove the bottleneck. It’s going to help move people and goods through the region.”

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