By CHRISTINA RITCHIE ROGERS
In anticipation of next year’s redesign of the I-77 / Catawba Avenue interchange, town officials now are looking at ways to alter the adjacent intersections – at U.S. 21 and Torrence Chapel Road – to better handle the new traffic pattern. Ideas include a traffic circle and changes to traffic signal cycles, but consultants last week said that even the best models have a shelf life of 15 years or less.
Exit 28 next year will be converted to a Diverging Diamond Interchange (DDI), a unique design that trasnportation officials say will improve traffic flow and safety. The design calls for the eastbound and westbound traffic on the highway overpass to cross to the opposite side at the freeway, to avoid left turns across multiple lanes of oncoming traffic and allowing cars entering and exiting the freeway to do so more smoothly.
DOT officials estimate the new interchange will cost around $3.5 million of the $6 million in federal funds approved for the project. For the past year and a half the town has sought approval to use the leftover $2.5 million to ensure the adjacent intersections can handle the increased traffic flow from the DDI.
The Federal Highway Administration (FHWA) recently gave NCDOT the OK to spend the leftover funds on upfitting these so-called “bookend” intersections, as long as the changes help the I-77/Catawba interchange, Assistant Town Manager Andrew Grant said.
With the funding now available, town staff members have begun to “take a first look at what our options are” for the bookends, Mr. Grant said. Still to come are months of planning and public hearings on the project. Ideas so far include:
- The Paperclip: Build an oval-shaped traffic circle that would connect Burton Street, South Hill Street, Holiday Lane and U.S. 21 with Catawba Avenue.
- Liverpool/Torrence Chapel 2-phase conversion: In the short-term, add additional northbound and southbound turn lanes approaching the W. Catawba intersection and eliminate the split-phasing turn signals; In the long-term, convert to a “left-over” intersection, where cars in either direction may only turn right onto W. Catawba.
But preliminary traffic studies and research by Kimley-Horn & Associates shows that while certain designs would help with traffic flow in the short-term, the intersections likely would be inadequate by 2030, according to senior vice president Steve Blakeley.
“It’s going to fall apart,” Mr. Blakeley said at a Town Board pre-meeting April 2.
Kimley-Horn concluded that redesigning the bookends would have “significant property impacts,” would result in “minimal operations improvement” at the intersections, and would ultimately result in “traffic gridlock” based on 2030 projections. Even the best plans don’t change the fact that the population continues to grow, and W. Catawba Avenue remains just two lanes. All cars traveling east / west ultimately would need to feed back into just one lane each direction, consultants said, and recommended further evaluation of what they call the “root problem”: Catawba Avenue capacity.
As part of the planning process, officials will hold public hearings and seek input from citizens, land owners and business owners, Mr. Grant said. The town will not have a final cost estimate for the bookends project until it has a final plan, he said.