[markbnj]

My first thought on reading the post was to ask whether an analysis of roads strictly in terms of aggregate capacity even makes sense? It seems to me you have to ask where people are, where they need to go and why. Between any two travel points you can perform a capacity analysis, but doing so in the aggregate would, I think, shortchange a lot of smaller places.

[remarkEon]

Another Midwesterner, here (Minnesota, with family in Iowa and South Dakota). I think you're correct on the potential to shortchange a lot of the smaller towns. For example, the high school my dad went to (a long time ago, in a galaxy far far away) has since been consolidated with 2 other school districts, so some of the demand for roads has shifted to more of the main highways instead of a lot of the smaller, more rural roadways. Same thing happened to the school districts my cousins went to in South Dakota. Now, for the most part, they travel on I90 and I29 to Sioux Falls. I think the gp is correct in saying that "the entire system is unneeded" is a bit of a hyperbole. But I'd be curious to see what their DOT's plans are for collecting data on that capacity usage, and how it will play out, politically, if there are serious proposals to start to rein in spending on rural road upkeep in low usages places.