Appalachian Development Highway System (ADHS) Corridor K Improvements

Corridor K is part of the Appalachian Development Highway System (ADHS) through western North Carolina.  Mountains and rich natural and cultural resources present numerous design challenges. Given these factors, Corridor K is among the last ADHS corridors to be completed—but it’s very much needed as the current roadway network is limited to steep, curvy, two-lane roads through areas prone to frequent rockslides.

We supported development of a new, integrated planning approach that focused on local engagement and meaningful collaboration with the public, environmental stakeholders, and agency staff, while aligning with the National Environmental Policy Act (NEPA) and other regulations. The result? A context-sensitive design that reduces environmental impacts over previous proposals and provides a process for Tribal and agency oversight in the construction phase. The design also includes a land bridge to facilitate wildlife movement and reduce visual impacts seen from the Appalachian Trail. Our coordinated planning approach streamlined identification of the preferred alternative within fifteen months after initiating formal NEPA studies. Interagency coordination and the entire NEPA documentation process was completed within a two-year timeframe. 

Our design helped improve ADHS Corridor K, one of the most complex transportation projects in the southeast United States.