What are the Appalachian Regional Corridors?
The Appalachian Regional Corridors are a system of proposed 4-lane highways designed to stimulate economic development in the Applachian Mountain Region. They each have letters. For more information see http://www.arc.gov/index.do?nodeId=1006 and http://www.aaroads.com/arc/ (the latter has a chart of corridor letters and corresponding route numbers).