I was looking at a map of the US that had on it the Interstate Highway System. I happen to be looking at East-West Interstates that cross most, if not all of the US. For example, you can jump on Interstate 80 in San Francisco, CA and drive all the way to Teaneck, NJ, which is a little over 2,900 miles.
As I was looking at the map I noticed something. If you start in North Dakota, and work your way south to Texas you find a number of E/W Interstates that span the country; I-90, I-80, I-70, I-40, and I-10. What you don’t find is I-60, I-50, I-30 and I-20? Were they ever planned, or is the numbering systems the way it is for a specific reason?
Okay, there is an I-20, but it starts in West Texas and heads east from there.