My dad took me and my sister on a road trip recently and we noticed all the highways are named with numbers. I was wondering if there was a pattern to it or if the numbers were just random.
Reviewed by Shannon Martin, Licensed Insurance Agent.
Interstate numbers might seem random—but they’re not! In fact, highways are numbered in a specific order based on the Interstate Highway System developed back in 1957:
Most major interstates are given one- or two-digit numbers
Highways that run east to west are given even numbers
Highways that run north to south are given odd numbers
Here are some general rules:
If the road is considered an Interstate or Route, the numbers will increase from west to east and from south to north
If it’s considered a Highway, the numbers increase from east to west and from north to south
Interstates with three digits are usually shorter than the one- or two-digit highways and serve to connect larger interstates.
There are some exceptions to these rules—but in general, most US Interstates and Highways follow this numbering convention.
Before you head out on your next family road trip, download the
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