I-26 Palmetto Commerce Interchange is a new interchange in North Charleston designed to the South Carolina Department of Transportation and Federal Highway Administration guidelines. Upon completion, the interchange will improve mobility and serve as a direct route in and around Palmetto Commerce Park. The new link, which will include approximately 0.5 miles of four-lane road, will relieve major traffic congestion along these heavily traveled roads and an extremely busy segment of I-26.

Charleston County commissioned Davis & Floyd to provide overall project management and roadway bridge, interchange, and drainage design.

Intersection, Bridge, & Roadway Design

The currently proposed solution is a three-point Urban Diamond Interchange between the US 78 and Ashley Phosphate Boulevard exits on I-26 with pedestrian access and a new traffic signal. This connection will relieve local roadways, especially Northside Drive, reducing traffic by at least a third. The design provides a smaller footprint, reducing the impact to low-income housing units north of the interchange. The new overpass will include a barrier-separated, multiuse path that will connect north and south sides of the interstate with pedestrian and bike traffic. Roadway design includes interstate ramps and connection to Weber Boulevard.

Public Involvement

We conducted two public information meetings and a public hearing. We also created reasonable alternative animations for the public meetings.

Landscape Architecture

We provided landscape and hardscape design to tie in with Ingleside Boulevard’s details and lighting. The slope adjacent to the mobile home park is landscaped as a visual barrier to the interchange traffic.


  • Bridge/Overpass Design
  • Drainage Design
  • Environmental & Permitting
  • Hydrology & Hydraulic Design
  • Interchange Justification Report
  • Landscape Architecture
  • Project Management
  • Public Involvement
  • QA/QC
  • Right-of-Way Acquisition
  • Roadway Design
  • Survey
  • Utility Coordination
  • Video Animation