Pub. L. 106-181, tit. II, subtit. A, sec. 205
DETERMINATION OF DISTANCE FROM HUB AIRPORT.
SEC. 205. DETERMINATION OF DISTANCE FROM HUB AIRPORT. The Secretary may provide assistance under subchapter II of chapter 417 of title 49, United States Code, with respect to a place that is located within 70 highway miles of a hub airport (as defined by section 41731 of such title) if the most commonly used highway route between the place and the hub airport exceeds 70 miles.