Long-term transportation planning
CDM Smith began planning in 2009 to establish new road and rail alignments, secure right-of-way, and support development of infrastructure.
The Cosgrove Ave. Extension bridge is a key connection serving the South Carolina State Ports Authority’s Navy Base Intermodal Facility and surrounding North Charleston neighborhoods. CDM Smith partnered with SCPA to provide planning, preliminary design, final design and construction support for the bridge as part of a larger package of roadway and bridge improvements. By carrying traffic over the facility’s new north rail lead, the bridge creates a critical grade separation while improving access to ongoing development at the former Charleston Navy Yard.
CDM Smith began planning in 2009 to establish new road and rail alignments, secure right-of-way, and support development of infrastructure.
The team developed preliminary and final designs for multiple bridges, including the Cosgrove Ave. Extension bridge, providing grade separation over the new north rail lead serving the intermodal facility.
Designed as a four-lane urban arterial with a shared-use path and ornamental railing, the bridge improves connectivity between North Charleston neighborhoods and emerging commercial developments.
The team continues to provide design support during construction as the bridge and roadway improvements move toward completion.
The Cosgrove Avenue Extension project represents more than a decade of planning, design, and collaboration. After planning began in 2009, the project advanced through preliminary design in 2012 and final design in 2014 before construction started in 2023. The bridge was opened for the public in July 2026, with adjacent bridge and roadway improvements scheduled for completion by the end of the year. The project was completed by our Columbia and Charleston offices in South Carolina, with support from Charlotte, Lexington and Knoxville. Once complete, the improvements will support access to the Navy Base Intermodal Facility, which is expected to begin operations in late 2027, strengthening freight movement and economic development throughout the region.