Via CityLab, Here’s a map that, if I hadn’t told you, you probably wouldn’t be able to figure out. It’s the US mapped according to the percentage of curved roads:
Here’s the description from the creator, who readily admits his data is flawed in that OpenStreetMap is not yet complete:
The Mid-west USA and Canadian prairies have the most straight roads. Nearly all of the roads there are straight. This broadly matches my theory.
Q: Does this explain anything at all about Midwestern sensibilities?