Interstate Numbering System and How to Decode it

You probably know the roads pretty well in the area where you live, but when you head out to unfamiliar territory, highway and other route signs become more important. Most people don't know that many highway, road marker and exit signs contain useful information other than just their number. Signs are communicating with you, to let you know where you are at all times. Knowing what the numbers on Interstate signs have to tell you can be a great aid to navigation.