Our distances are not driving distances, but are calculated as a 'straight-line' distance from Interurban Heights. A straight line distance ignores things like rivers, canyons, lakes, et cetera - it's truly a line drawn from Point A (ie- Interurban Heights) to Point B.
Our distance measurements begin at a specific point in Interurban Heights. The point that we are using is located at these GPS coordinates - Latitude: 33.4815, Longitude: -86.9142 [Map]. In this case, the coordinates for Interurban Heights have been provided by the Geographic Names Information System (GNIS).