The Project
The segment of US 17A (North Main Street) from Farmington Road/Sigma Road to Sangaree Parkway/Brighton Park Boulevard is a 3.25-mile, five-lane curb and gutter commercial corridor. The heavily traveled corridor (41,900 AADT) includes 15 intersections, six of which are signalized, and numerous driveways. Because the undivided corridor experienced high crash rates associated with angle crashes, SCDOT identified this segment as a priority corridor for safety improvements (US 17A Road Safety Audit, 2020).
To conduct the traffic analysis and forecast, RK&K used the BCDCOG Travel Demand Model. Based on this model, corridor traffic is expected to grow at annual rates approaching 3.5% over the next 25 years. After performing traffic operations and safety analyses and access management studies, RK&K developed improvements that addressed safety and access management while minimizing impacts to utilities and right of way. SCDOT selected the preferred alternative, which achieved the highest benefit-cost ratio, based on the nature of the proposed safety and operations enhancements versus the overall cost.
To garner public comments, RK&K held an open forum public meeting, providing SCDOT with content for its project website, postcards, flyers, meeting displays, and comment forms. During the public comment period — two weeks before and after that public meeting — RK&K provided responses to every comment received. RK&K also coordinated heavily with the Berkeley-Charleston-Dorchester Council of Governments (BCDCOG) and worked with officials from SCDOT’s Traffic Safety office and District 6 Traffic.
RK&K’s design included a concrete median, converting the painted median to a raised one. To facilitate business access, multiple unsignalized restricted crossing u-turns (RCUTs) were added within the raised median based on owner feedback and SCDOT District input. The crown of the road was in the median, which posed drainage challenges. To mitigate drainage issues, the raised median included flumes to direct stormwater, and left turn lanes included cross slope corrections to eliminate stormwater ponding.
Other design elements included:
- Additional turn lane storage at intersections
- U-turns along the corridor
- Enhanced signal improvements
- Restriping
These improvements eliminated the need for additional right of way acquisition and minimized closed drainage system installation in the median. While utility conflicts occurred at intersections where the design added turn-lane storage, overall utility impacts were minimal, and our team worked with utility stakeholders to facilitate relocations. The team also worked with both utility owners and the SCDOT District Utility Office to design in-place pipe protection during construction.
Due to heavy traffic volumes on US 17A, traffic control during construction was a concern. RK&K’s Maintenance of Traffic (MOT) plan included night work, lane closures, and traffic shifts for the median work to minimize traffic interruptions.
The segment of US 17A (North Main Street) from Farmington Road/Sigma Road to Sangaree Parkway/Brighton Park Boulevard is a 3.25-mile, five-lane curb and gutter commercial corridor. The heavily traveled corridor (41,900 AADT) includes 15 intersections, six of which are signalized, and numerous driveways. Because the undivided corridor experienced high crash rates associated with angle crashes, SCDOT identified this segment as a priority corridor for safety improvements (US 17A Road Safety Audit, 2020).
To conduct the traffic analysis and forecast, RK&K used the BCDCOG Travel Demand Model. Based on this model, corridor traffic is expected to grow at annual rates approaching 3.5% over the next 25 years. After performing traffic operations and safety analyses and access management studies, RK&K developed improvements that addressed safety and access management while minimizing impacts to utilities and right of way. SCDOT selected the preferred alternative, which achieved the highest benefit-cost ratio, based on the nature of the proposed safety and operations enhancements versus the overall cost.
To garner public comments, RK&K held an open forum public meeting, providing SCDOT with content for its project website, postcards, flyers, meeting displays, and comment forms. During the public comment period — two weeks before and after that public meeting — RK&K provided responses to every comment received. RK&K also coordinated heavily with the Berkeley-Charleston-Dorchester Council of Governments (BCDCOG) and worked with officials from SCDOT’s Traffic Safety office and District 6 Traffic.
RK&K’s design included a concrete median, converting the painted median to a raised one. To facilitate business access, multiple unsignalized restricted crossing u-turns (RCUTs) were added within the raised median based on owner feedback and SCDOT District input. The crown of the road was in the median, which posed drainage challenges. To mitigate drainage issues, the raised median included flumes to direct stormwater, and left turn lanes included cross slope corrections to eliminate stormwater ponding.
Other design elements included:
- Additional turn lane storage at intersections
- U-turns along the corridor
- Enhanced signal improvements
- Restriping
These improvements eliminated the need for additional right of way acquisition and minimized closed drainage system installation in the median. While utility conflicts occurred at intersections where the design added turn-lane storage, overall utility impacts were minimal, and our team worked with utility stakeholders to facilitate relocations. The team also worked with both utility owners and the SCDOT District Utility Office to design in-place pipe protection during construction.
Due to heavy traffic volumes on US 17A, traffic control during construction was a concern. RK&K’s Maintenance of Traffic (MOT) plan included night work, lane closures, and traffic shifts for the median work to minimize traffic interruptions.
