To understand U.S. culture in the 21st century, don't start with pop music icon Britney Spears. Definitely don't start with pop intellectual icon Jacques Derrida. Start with the highways. While Jacques and Britney have affected our culture in significant ways—changing the way we look at novels and navels, respectively—neither can take credit for literally changing the way Americans see their country.

One hundred fifty years ago, if you asked a person to sketch a map of the United States, that map almost certainly would have included rivers—not just the Mississippi, but also the Ohio, the Missouri, the St. Lawrence, and more. As both barriers to and corridors of transportation, rivers were defining features of North America. Cities invariably arose at a conjunction of rivers or at a deep-water port.

Today most Americans would be hard-pressed to draw the location of any river except the Mississippi. But the grid of highways now defines our landscape. From "the 5" in the West to I-95, which The New York Times recently called "the Mississippi, the Nile, and the Euphrates of the East Coast, rolled into one," interstates are our rivers. Today, the United States' fastest-growing commercial areas are at the intersections of interstate highways.

The interstate highway system is a telling example of culture, which Ken Myers neatly defines as "what we make of creation—in both senses of the word make." Culture goes much deeper than music or books. It encompasses every human effort to fashion something out of the world.

As Myers suggests, however, culture is not simply what we make from the world's raw materials. It is also the way we make sense of the world—that second meaning that Myers hints at. Even something as prosaic as an interstate ...