Video from the North Carolina Department of Transportation shows the completed causeway along I-40 in the Pigeon River Gorge.

The N.C. Department of Transportation has installed about 123 monitors along the highway to detect any movement of the slopes along the river.

The rule, first established in 2001 by the then-outgoing Clinton administration, allows the federal agency to designate “inventoried roadless areas” within the National Forest System.