Diverging diamond opens on Poplar Tent Road

State transportation engineer Davis Diggs has advice for motorists encountering North Carolina’s first diverging diamond interchange.

“Just follow the signs,” Diggs said Monday morning as he watched drivers negotiate the new intersection on Poplar Tent Road at Interstate 85 in Cabarrus County. “Even if it looks different to you, just follow the signs and you’ll have no problems.”

The intersection takes motorists to the opposite side of the road but also eliminates the need for left turns across oncoming traffic at signals. It opened Sunday evening, adding North Carolina to the list of more than 15 states with a type of intersection innovative enough to have its own website.

The N.C. Department of Transportation said eight diverging diamond interchanges (or DDIs) are under construction, including four in the Charlotte area. Another such interchange over I-85, at N.C. 73, will open late next month, Diggs said. Others are being built on Catawba Avenue over Interstate 77 in Cornelius, and on Mallard Creek Road over the future final leg of Interstate 485 in north Charlotte.

“The DDI allows for an easier flow of traffic,” Diggs said. “We’ve put up a lot of signs and markings, and we’re asking the public to pay attention to those signs. If they do that, we should be fine.”

The diverging diamond interchange has two traffic signals – one at the entrance to the intersection, where traffic crosses to the opposite side; and one at the end, where motorists return to the right side of the road. Diggs said the signals are “two-phase lights,” meaning motorists are dealing either with red or green, and no turn arrows.

Ryan Lowder, project manager for Lane Construction, which built the intersection, said Poplar Tent Road currently has one-lane traffic approaching the interchange but said there will be two lanes in each direction eventually. “We thought that might prove to be a bottleneck at the end of the interchange, but it hasn’t been the case so far,” he said.

Diggs stood at the entrance to the interchange Sunday evening and watched the traffic flow. He said there were “a few hiccups” by motorists in the first 12 hours of the interchange.

“You could see the wide eyes on a few motorists as they neared that first traffic signal,” he said. “But if you just follow the signs, there will be no problems.”

The diverging diamond interchange requires a smaller “footprint” than a typical interchange, and Davis said the DOT was able to save enough money on property acquisition to pay for the work, which is part of the I-85 widening project.

Motorist Joey Doolittle of Kannapolis said he had no problems with the interchange on Monday.

“No, it was smooth,” he said. “I just watched the signs, and it went fine.”

Doolittle found an additional advantage to the interchange. “It looks a lot better now, with all those traffic cones gone,” he said.