WVDOH eyes divergent diamond to replace Exit 153 roundabout

MORGANTOWN — A little over two years after the University Town Centre tax increment financing (TIF) district funded the construction of a new, $22 million interchange, it appears as if a significant redesign is en route.
Specifically, the West Virginia Division of Highways (DOH) is looking at reconfiguring the traffic flow at the University Town Centre exit, Exit 153, by eliminating the roundabout and replacing it with a divergent diamond interchange (DDI).
Preliminary estimates provided by the DOH put the redesign at around $7 million. It is anticipated this funding will also come from revenue generated by the TIF district.
An informational open house was held Wednesday at the Monongalia County Ballpark to show off the fairly recent DDI concept and collect public feedback.
HDR Engineering Senior Project Manager Domenic Sacchetti said his firm was brought in to perform traffic studies tied to ongoing WestRidge development along I-79. He said it was quickly determined that the existing roundabout setup would not handle the traffic generated by the amount of development taking place.
“In a regular intersection where you have left turns, the signal has three to four phases, so it’s a long cycle time,” Sacchetti said. “With the DDI, it basically eliminates the left turn phase from each intersection, so each signal only has two phases and they’re timed so that once you hit the first one, you go straight through.”
HDR Traffic Engineer Judith Iszauk said the DDI design originated in France. She said the fist one to be built in the U.S. was completed in 2009, in Missouri. There are currently 90 operating DDI interchanges in the U.S. with dozens more in various stages of development.
The closest operational DDI is located at I-70 and Pa. 19, near Washington, Pa. It was opened in 2017, replacing a cloverleaf interchange.
While Sacchetti said roundabouts are effective at aiding traffic flow, they bog down when so much traffic is trying to enter the circle that cars begin to queue in the access points, often resulting in the placement of traffic lights, which defeats the original purpose.
“Roundabouts are great. They work, but with very high traffic volumes they become difficult,” he said.
Monongalia County Commission President Tom Bloom said the amount of development taking place in the area is ahead of schedule and beyond what was previously anticipated. He said he understands people may take issue with the expenditure of TIF funds to redesign a two-year-old interchange, but the changes have been made  necessary by the amount of growth.
“This is going to be like anything else. It’s going to take time to get used to,” Bloom said. “I think the public will come to really like this. We’re just going to have to drive it and get used to it.”
Sacchetti said the goal is to get DOH plan approval by next spring and have the new configuration opened to traffic a year from now.
Anyone wishing to provide feedback on the proposed changes can visit the WVDOH website, at or send comments to Mr. R.J. Scites at the WVDOH at 1334 Smith Street, Charleston , W.Va. 25301.
Public comments are due by Nov. 26.
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