substantial impairment

Isaac Kremer/ November 23, 2025/ / 0 comments

Impacts of a U.S.-funded transportation project that are so severe that they substantially diminish or impair the protected activities, features, or attributes that qualify a resource for protection under Section 4(f) of the Department of Transportation Act of 1966, such an increase of noise levels at a historic site with a traditionally quiet setting, or obstruction of the primary views of an architecturally significant building, or structural damage caused by vibration. See also constructive use. (Bucher, 1996)