By DAVID BORAKS
The N.C. Department of Transportation plans to award a contract next month for rebuilding Exit 28 off I-77 into a “diverging diamond interchange,” a project that is aimed at improving traffic flow across and on/off the highway. Town officials also have been told the road project could take up to two years, as the DOT limits most of the work to nights to prevent major traffic headaches.
The biggest disruption will come during an as-yet unscheduled weekend when the Catawba Avenue overpass will be closed for about 32 hours, town officials said this week. That will allow workers to convert the parallel east-west lanes on the bridge to the new “diverging diamond” pattern.
Traffic will be limited to one lane in each direction on Catawba Avenue for about four months during the work, both day and night. That’s when workers will be installing new concrete medians, walls, permanent traffic signals, and sidewalks.
The two-year time frame came as a bit of a surprise to Cornelius officials. Assistant Town Manager Andrew Grant said at Monday’s Town Board meeting that the long project is a trade-off, to avoid major daytime disruptions. That’s a major concern for local businesses, and town officials have promised to work with the DOT to minimize the impact on nearby stores that rely on local traffic.
“They really think it’ll take 24 months,” Grant said. “I think a lot of that is because a lot of the construction is going to take place night.”
The DOT also has pledged not to allow any lane closures during major holidays and big regional events, such as NASCAR races at Charlotte Motor Speedway.
NEW TRAFFIC PATTERN, NEW LOOK
The N.C. Department of Transportation is in the midst of planning a $3.5 million overhaul to the Exit 28 interchange. The project could begin as early as this October, and is expected to last into 2014.
The project is designed to improve traffic flow and safety. In the “diverging diamond” design, the two directions of traffic on the overpass will cross over one another to the opposite side of the bridge at the freeway. That will prevent cars from from having to turn left across multiple lanes of oncoming traffic onto the highway.
It also will allow cars to enter and exit the highway more smoothly. The new ramp design also could make drivers’ wait time five times shorter, officials have said.
When the interchange is rebuilt, the interchange also will get a big aesthetic makeover, in a roughly $2 million companion project that the Town of Cornelius will pay for. Contracts for that work are expected to be signed at the same time as the reconstruction project.
[The town spent $200,000 in fiscal 2013, and expects a similar cost in the current financial year, fiscal 2014. Town officials expect the project to cost another $1.6 million in fiscal 2015. The money is coming from the town's capital projects budget, which is funded annually.]
Town officials have pushed for the changes in hopes of creating a prominent new gateway to the town and to Lake Norman. Plans call for a nautical-themed design with decorative bridge abutments, 5-foot lanterns at four corners, a central pedestrian walkway on the bridge, and trees and other plantings.
The most striking element will be a pair of mast arms with cables to suggest sailboat masts and sails. There’s even a space on the bridge abutment that could include include the town name in some kind of public art project.
Town officials say the construction zone will be along I-77, on the Catawba Avenue bridge, on ramp, and the area next to the bridge along West Catawba and Catawba Avenue. The area is roughly from Torrence Chapel Road on the west to Highway 21 on the east.
The town said traffic will be affected as follows:
- On the interstate – I-77 traffic will flow normally during daylight hours and rush-hour traffic times. When necessary, there will only be one lane (in each direction of I-77) closed during the night (non-rush hour times); thus, work could occur generally from 9 pm – 6 am the next morning (Sunday night – Friday morning) and 9 pm – 9 am the next morning (Friday night – Sunday morning).
- Catawba Avenue corridor – To minimize interruptions to normal traffic flow, the majority of construction will take place at night, generally from 9 pm – 6 am the next morning (Sunday night – Friday morning) and midnight – 8 am the next morning (Friday night – Sunday morning); however, there will be significant periods during the project that construction must occur during daylight hours. During almost all times, there will always be at least one lane in each direction (east and west) going across the bridge. On occasion, at night, there may be a full stop of traffic for periods of time not to exceed 15 minutes.
- Total closure – There will be a 32-hour continuous period of time that the bridge will be closed to thru traffic crossing the bridge, to allow for a shift in the traffic pattern to the diverging diamond pattern. This will occur during a single weekend between midnight Friday and 8 am Sunday.
- Four months with one-lane each direction – There will be a four-month continuous period of time that traffic will be limited to only one-lane of traffic in each direction across the bridge, during all day and night hours. This will allow for construction of substantial concrete medians, walls, permanent traffic signals, and sidewalks.
Town of Cornelius latest update on the Exit 28 project, Cornelius.org
See how the diverging diamond traffic flow will work in a video on YouTube.
See images of the proposed aesthetic re-design of the interchange (PDF).
Previous coverage of the diverging diamond project under the DDI tag