The graphic language of the London Underground map is so iconic that "[insert any network or process here] visualized as a London Underground map" has become a design cliché. So why are we writing about the latest iteration, a Tube-style map of U.S. interstate highways, created by Cameron Booth? Because, clichéd or not, visualizing this particular system in this way is actually damned useful.
The U.S. interstate system actually has a grid-like logic to it: Highways that go north/south are labeled with odd numbers, and highways that go east/west have even-numbered labels. Not that you’d be able to easily tell, though--much like the London Underground rail system, interstate highways look like an overturned plate of spaghetti when plotted on a geographically accurate map. I remember getting confused all the time when I was a kid living in northern Illinois: I-94 technically goes east/west, but between Chicago and Milwaukee, it actually goes north/south.
Chucking geographic accuracy for a Tube-style schematic makes much more sense for plotting routes on the U.S. interstate system. Like the London Underground, the interstate highways are all about connecting nodes and skipping the stuff in between. On the Tube, there’s no scenery between stations; as far as a rider is concerned, it’s like riding an elevator. So who cares if the clean, orthogonal lines connecting stations don’t completely correspond to geographic reality as long as the endpoints do?
Interstate navigation is the same: When you’re driving from New Jersey to San Francisco, you want to know which line will get you from point A to point B. You already know you’ll be generally traveling in a westbound direction, so why not just show I-80 as a nice, clear, straight red line cutting across the U.S.? It’s also useful to know what other major cities (and interstate connections) you’ll be passing through. No problem: Just like on the Tube map, cities are "stations" and intersections are "transfers."
Planning a cross-country trip with this map--and navigating your way during it--can be accomplished in seconds, and the map can be easily miniaturized without becoming hard to use. Sure beats fumbling with a Rand McNally map that never folds right, takes up the entire dashboard, and requires a jeweler’s loupe just to read. Maybe some enterprising member of the American Association of State Highway and Transportation Officials--which designed the numbering system in the first place--could strike up a clever licensing deal with the London Underground and make this map official.