Comments on: The Math Inside the US Highway System

By: sarreq

sarreq — Wed, 05 Aug 2026 19:23:38 +0000

This is the US Interstate System (I-##), not the older US Highway/Route System (US-##). the US Route system designated low odd numbered routes counting up from east to west, thus I-95 runs roughly along the same corridor as US-1, while US-101 (technically still considered a 2 digit route, so ten one, rather than one hundred one) runs parallel-ish to I-5. the east↔west US routes count up from north to south. basically, the Interstates took the same system as the US Routes, but inverted it's orientation.

By: Gary C.

Gary C. — Wed, 23 Dec 2020 02:41:48 +0000

Wisconsin really gets disrespected here; factual errors in TWO charts. In the abstract map, where I-90 is shown to turn 45 degrees between Chicago and Albert Lea, there should be a line representing I-94 continuing on the diagonal direct to MPLS/St. Paul. In the upper map (full US) there is a reference to I-57; while that was the proposed route number, I-57 does not exist north of Chicago, IL; in the early 2000's, when this article was written, that line would have been I-43, the number assigned in 1987. From Milwaukee, I-43 angles SW to Rockford, IL. You can be forgiven for not mentioning I-39 and I-41, they came around later.

By: Cory

Cory — Thu, 09 Aug 2018 03:45:00 +0000

Someone told me, or I noticed, early on that thee higher numbers were in the North and the lower ones in the South. Eventually the whole system was explained to me. I love the simplified map on a grid. Great post!

By: Larry

Larry — Thu, 31 Aug 2017 17:04:15 +0000

It's heartbreaking to read the comments from people who's natural curiosity and desire to learn was crushed by incompetent teachers who I've had power and authority over them (try arguing with a nun). I want to tell them that its never to late and they should pursue their dream, even if they won't go on to make me discoveries. They can still experience the joy of "discovering" for themselves the hidden relationships that govern everything in the natural world.