Monday morning the Gold Hill Road bridge over I-77 will be unlike any in the state of South Carolina. York County will unveil the first ‘diverging diamond’ overpass, allowing for faster traffic flow, and reduced backups. Approximately 25,000 vehicles per day cross the bridge, and of the three plans for improvements that were considered, the diverging diamond showed the biggest improvement in traffic flow, said York County Assistant County Engineer Patrick Hamilton.
A Diverging Diamond Interchange is a diamond-shaped interchange that allows vehicles in two lanes to temporarily cross to the left side of the road, travel the bridge, then cross back to the right side. This makes traffic move easily through an intersection without increasing the number of lanes and traffic signals. It’s designed for high-volume traffic areas.
Construction on the project began in the Summer of 2019, at a cost of $14.5 million. York County’s Pennies for Progress program is paying $12 million of that cost, with the remaining $2.5 million funded by grants. Boggs Construction was the lead contractor on the project. The bridge will close Friday September 10th at midnight, but there will still be access to the interstate in both directions using the ramps. The new bridge is expected to open at 5am Monday morning. Construction will continue after the bridge is open, and is expected to be completed by late October.
Below is a link to a 3-minute video detailing how a diverging diamond works for traffic coming from all directions.