Post whatever random facts about interstates or US routes you have that you find interesting here. They can be as obvious, or as obscure as you like. I had plenty of facts over the past few weeks, but forgot about what all of them are about. Here's two I thought of in the shower today:
Of the x0 interstates (excluding wannabe I-30), I-10 interchanges with the most x5 interstates, while I-70 interchanges with the least. And none of them meet all 10 of them.
90: 5, 15, 25, 35, 55, 65, 75, 95 (8)
80: 5, 15, 25, 35, 55, 65, 75, 95 (8)
70: 15, 25, 35, 55, 65, 75 (6)
40: 15, 25, 35, 55, 65, 75, 85, 95 (8)
20: 35, 45, 55, 65, 75, 85, 95 (7)
10: 5, 15, 25, 35, 45, 55, 65, 75, 95 (9)
Speaking of I-70, it's the only x0 without a 5xx 3di, a common odd first digit for 3dis for some reason, and sometimes, the only odd first digit 3di an interstate has (516, 520, 530, 579, etc). Also, I-40 doesn't have a 3xx 3di, another common first digit.
Interesting.
I have always thought about how the I-35/I-10 interchanges in San Antonio are the most "connected" interchanges in the system (fitting since they share an alignment too). Since the aforementioned I-10 intersects with the most I-X5s and I-35 is the only I-X5 to intersect with all I-X0 interstates (I am not going to fight about how I-35 is actually 3 separate interstates and that it doesn't intersect with I-20 or I-30 since they actually intersect I-35E and I-35W from east to west respectively). Basically the only one missing is I-85, but a short jaunt up I-65 from Mobile gets you to I-85 so it can be easily forgiven.
Separately, I-30 and I-85 are cousins, as they are the only interstates to default on both ends onto another "like" interstate (I-85 from I-65 to I-95 and I-30 from I-20 to I-40), making their short or relatively short life being part of a much larger route.
On that note, I am not in the boat of the I-30 and I-45 bashing. I-30 is an important connection from Dallas to Chicago or New York, while I-45 is basically I-35EE, part of that important corridor. Yes they are both short, but very important.