Protected areas
Protected areas means all areas inside the boundaries of a State which are adjacent to and within 660 feet of the edge of the right-of-way of all controlled portions of the Interstate System within that State. Where a controlled portion of the Interstate System terminates at a State boundary which is not perpendicular or normal to the centerline of the highway, protected areas also means all areas inside the boundary of such State which are within 660 feet of the edge of the right-of-way of the Interstate Highway in the adjoining State.
Source
23 CFR § 750.102
Scoping language
The following terms when used in the standards in this part have the following meanings: