"Things You Wouldn't Know If We Didn't Blog Intermittently."
I regularly drive between Chicago and Vilas County, WI. If I read it correctly, this map is showing that my best route would be to drive West to somewhere around Galena, IL before turning northward to Northeast Wisconsin, adding a couple of hundred miles to the trip. "Not of any practical use" is an understatement.
This is not a map of best routes between two places. Only from the geographic center of the US to each county. It's a art project.
It appears that there are not many routes from the geographic center to points west. Is it the mountains? Deserts?
Mountains, mostly. Efficient road building calls for a mountain pass. Deserts are fairly easy to build roads upon.