Information on the Diverging Diamond Interchange being installed at Highway 133/Village Rd. and US 17/74/76 in Leland
Updated April 15, 2016
The N.C. Department of Transportation is in the process of installing a Diverging Diamond interchange at the intersection of Highway 133 / Village Road and U.S. 17/74/76 in Leland. The Diverging Diamond is scheduled to open at 6 a.m. on Monday, Apr. 18. Click here to sign up for Commissioner Frank Williams’ e-newsletter and periodic traffic alerts.
Road Closure: Weather permitting, NCDOT will close N.C. 133/Village Road/River Road at 9 p.m. on Friday, Apr. 15 to complete work on the new design; click here for information on the closure.
About the Diverging Diamond: The diverging diamond will drastically alter the traffic patterns at the intersection, and citizens need to be aware of the upcoming changes.
This post is intended to help Brunswick County residents understand how the new interchange pattern and traffic flow will impact and, hopefully improve, their commutes.
Resource Files:
Diverging Diamond Visualization: The following video was posted on the NCDOT’s YouTube channel in 2010. While the highway numbers referenced are different than those in our area, it will give you an idea of how the interchange will work. At this time NCDOT does not appear to have a video visualization specific to the Leland project.
Diverging Diamond Interchange Q&A
Taken from the NCDOT website. Click here for a printer-friendly PDF from the NCDOT website.
What is a Diverging Diamond Interchange? A Diverging Diamond Interchange (DDI) allows two directions of traffic to temporarily cross to the left side of the road. A DDI moves high volumes of traffic through an intersection without increasing the number of lanes and traffic signals. This movement provides easier access to an interstate.
How do motorists drive through a Diverging Diamond Interchange? If you look at an aerial picture of a DDI, you may think it could be a challenge driving through the intersection. But in reality, a DDI has pavement markings and traffic signals just like any intersection. When driving a DDI, motorists proceed through a traffic signal at the entrance to the interchange, and simply follow their lane to the opposite side of the roadway. Motorists needing to access the interstate turn left on the on-ramp without having to stop for additional traffic signals or wait for oncoming traffic to pass. Motorists needing to drive straight through the intersection proceed through a second traffic signal and follow their lane back to the right side of the road. Pavement markings and signals direct motorists to where they need to go.
How do pedestrians and cyclists use a DDI? Pedestrians use signalized pedestrian crossings and then are directed to a center pedestrian island in the middle of the road. Bicyclists can use a bike lane adjacent to the right lane or a median bike lane if one is provided.
What are the benefits of a DDI? A DDI reduces congestion by allowing traffic to keep moving through an intersection. It also improves safety by allowing free flowing turns when entering and exiting an interstate, eliminating the left turn against oncoming traffic and limiting the number of traffic signal phases. They are easy to navigate and eliminate last minute lane changes. The DDI provides better sight distance at turns which results in fewer crashes.
Is a DDI cost-effective? Yes. For improvement projects, a DDI can often be constructed using the existing bridge structure and the existing right-of-way, eliminating the cost of building new structures and purchasing additional right of way. Because many of the existing interchange features remain intact, the DDI is often constructed in less time then it would take to construct a new interchange and with significantly less impact to motorists. When constructing a new interchange, a DDI usually requires the purchase of less right of way and the construction of fewer lanes and bridge structures than traditional interchange types.
This information has been obtained from NCDOT and a variety of other sources and has not been independently verified.