Interstate Grid

Illustration of the intersections of cross-country US interstates
png · svg

On the US Interstate Highway System’s numbering plan, one- and two-digit interstates ending in an even number generally travel east/west, and those ending in an odd number generally travel north/south. The interstate numbers are lowest in the south and west, and get larger as they go north and east. Additionally, interstates ending in 0 or 5 are major cross-country routes.

Thus, if interstates followed the numbering system perfectly, the divisible-by-5 interstates should form a grid, from I-5 in the west to I-95 in the east, and I-10 in the south to I-90 in the north. I wanted to draw this grid to show where the major highways intersected.

However, a few of the divisible-by-5 interstates don’t quite conform to a grid. I-50 and I-60 don’t exist (since they would run through the same states containing US-50 and US-60, which could be confusing). I-85 crosses I-75 and ends up running west to I-65. I-30 and I-45 are both rather short interstates rather than the cross-country routes their numbers would indicate. And there are many instances where “parallel” interstates intersect.

Thus, the map got a bit more complicated than a simple grid. Inspired by Cameron Booth’s Interstate Highways as a Subway Map, I decided to use subway map language for my own project, while still keeping mine as close to an evenly-spaced grid as possible rather than a spatially-proportionate map. I also made the design decision to keep the intersections as metro areas rather than specific cities and suburbs for simplicity.

Tools

Vector Graphics Editor

License

Paul Bogard created this map, and has made it available for use under a CC BY-SA 4.0 License.