Actually, that doesn't mean that method is not transferable, it only means that the full proccess must be repeated on each city (or region) for it to make any sense. Measuring all those factors you talk about, and their effect, is exactly what the first part of this system does. Common sense may tell you that the local is in this or that ideal place, and will tell you that local will be very expensive as well. When you have to choose between two or three cheaper places, all worse than that ideal one, this method may be able to help you.

About that "Since most american families own a car, how the distance and time affect things is different than in Europe"... most european families do own cars. Our lower number of cars per capita does not translate as more families not owning a car, it just means that our families don't usually own more than two cars (i did not find the data for all Europe, but it is about 1.7 for Spain.