SC Route 46/170 Roundabout
Bluffton, SC

Thomas & Hutton provided concept development and engineering design services for the first multi-lane roundabout in South Carolina at the intersection of routes SC 46 and 170. The analysis and design were completed in accordance with AASHTO and SCDOT guidelines for roundabouts. The analysis and concept development evaluated several intersection designs based on safety, capacity, and compatibility with the surrounding area. A multi-lane roundabout was recommended and after coordination with the Town of Bluffton, area developers, Beaufort County, and SCDOT, the roundabout plan was approved and implemented.


The roundabout was designed based on rural roundabout criteria with bypass lanes to handle future high right-turn volumes. While the project was being constructed, traffic and lane closures were not allowed during peak travel hours. The project included pathways and crossings for pedestrians and cyclists.