CORNELIUS – The safety, efficiency and cost effectiveness when compared to new construction are all reasons why the Diverging Diamond Interchange at Exit 28 is slated to be worth the hassle of having lane closures over the next few months.
The Lake Norman Chamber of Commerce hosted an information session, led by Cornelius Assistant Manager Andrew Grant, about the DDI project on April 24. Attendees got a brief overview of the design, though no specific dates are available for when major lane closures on West Catawba Avenue at the I-77 juncture will occur.
Sometime in June, the bridge will be closed to all through traffic for a 32-hour continuous period. Drivers will be asked to use alternative exits and routes. Afterward, only one lane of traffic crossing the bridge in each direction will be open day and night for up to four months. The project completion estimation is this fall. All closures will be posted in advance through this newspaper and the town’s website.
Mayor Chuck Travis, who attended the meeting, said the goal is to minimize the impact to businesses in town.
The DDI came about as a cheaper alternative to rebuilding the Exit 28 bridge, which had an estimated price tag of $35 million. The project also won’t be affected by future I-77 widening projects.
The concept was started in France and entails both lines switching sides of the road for a brief period of time to make it easier to turn left without having to cross opposing lanes of traffic. Merging on and off the highway is safer and traffic flow is smoother with fewer stops.
“It’s a great bang for the buck,” Grant said, adding it nearly eliminates T-bone accidents.
The first state to implement it was Missouri in 2009, though more have been built. To ensure the project would fit well with Cornelius, Grant and other town staff visited the Missouri site when they were in planning stages.
“It was very underwhelming,” he said. “That's a good thing. When it comes to traffic you don’t want excitement or surprises.”
The DDI bridge also offers opportunities for art, landscaping and pedestrian walkways. People will be able to walk in the median in between the roads safely in what is planned to be a park-like atmosphere with trees and paths.
“We were standing in it and we didn’t feel unsafe and didn’t have to yell,” Grant said of the Missouri project. “It’s a good feature.”
The bridge will also have a mast and cables with lighting to give it a nautical bridge look to keep with Cornelius’ Lake Norman theme. The outside is also slated to be red brick, common for the area. A contest is also planned to make a decorative town sign on either side of the bridge.
“The key is for it to be a gateway for the town,” Grant said.
The construction projects planned for the bridge as well as other nearby intersections are to account for the increased number of drivers. Cornelius has seen tremendous growth in the last few decades, going from less than 6,000 in 1990 to quickly approaching 27,000. An estimated 27,000 drivers go over West Catawba each day. Exit 28 is the town’s only interstate interchange and is the primary connector to each side of town.
Other proposed construction projects to alleviate traffic are a roundabout at N.C. 21 and Catawba Avenue and a potential roundabout or other traffic study for the Torrence Chapel Road and West Catawba Avenue intersection.