Man Creates Humorous Animation To Explain The Complexities Of The Interstate Highway Numbering System

The open road has long had a great appeal for Americans. It is the ultimate symbol of freedom – just jumping in your car and driving for an unknown destination. The farthest I’ve ever driven in one go is from LA to Vegas. But someday, I’d love to do a real cross-country road trip and take in all the sights.

For anyone who has taken a road trip across the US, the roads you’re most likely to travel on are the US Interstate Highway.

This network of highways has a colorful past, including why they are numbered in the order that they are. One video from CGP Grey explains precisely how and why the numbering of the interstate highways works.

Grey begins by explaining, “The Interstate Highway shields hide within them long forgotten knowledge. As our great ancestors could navigate by the signs in the sky before the creation of the compass, so too before GPS could they navigate by these signs.”

Grey further elaborates the subtle differences, explaining that the Interstate Majors are the highways that run across multiple states from the east to west direction, and these are usually numbered in a two-digit number that ends with a 0, meanwhile the Interstate Majors going north to south in direction will typically be a two-digit that ends in 5.

As he shared in the video, “Together, the Interstate Majors constellation with its shining numbers lets you navigate the nation. The lower the numbers, the more South and West you are. The higher, North and East. If it ends in zero, you’re traveling horizontally. And if it ends in five, vertically.”

But it wasn’t just the Majors he talked about. Grey also included the Interstate Minors, which are three-digit deviations of the Majors, as well as Spurs and Interstate Mediums.

Grey said, “Interstate Minors diverge from a Major and have their last two digits match the Major from whence they came. Then, if the first digit is even, it means the Interstate Minor will eventually connect back to its parent Major. …The Interstate Mediums follow the same numbering pattern as the Majors, all two digits, if we keep those leading zeros in our hearts. Evens: East-West. Odds: North-South.”

Granted, like everything in life, there are some exceptions. And the complex highway system has its exceptions too, such as Interstate 99, Interstate 495, and Interstate 238, as well as varying duplications to the numbers.

Grey added, “…interstate I-495 aka the Long Island Expressway aka the L.I.E. …The is the spinal spur of the Long Island fish, never connecting back to its parent I-95 because Long Island is an island. But as a one-way spur it should start with an odd digit, not an even. And it really should be a two-digit Interstate Medium because it technically doesn’t connect to I-95 at all …A worse exception on the other coast in San Francisco is Interstate 238. Which the number tells you should be a bypass off of I-38. But no, I-38 doesn’t exist. I-238 is a one-way spur connecting two other Interstate Minors: I-580 and I-880.”

Watch the full explanation below:

How far have you traveled on the Interstate Highway? What is your favorite route? Let us know!