Very true. That the roads between these cities mostly go through sparsely-populated rural areas helps. EDIT: Though, the point I wanted to make was that it was

Very true. That the roads between these cities mostly go through sparsely-populated rural areas helps. EDIT: Though, the point I wanted to make was that it was an abstraction over the longer distances between the cities. To rephrase my examples, it's 360mi to Dallas, 430mi to Denver, 260mi to OKC, and 600mi to Houston. (Now that I'm looking up distances, I can add 500mi and 7.5 hours to Austin in that list - that length isn't in my cache, so to speak.)