What's the Difference Between a Dual Signed Road and a State Route?

There's a lot of things that we're not included, and one of them is that a lot of places are dual signed. You can also run into some weird situations where a route is both of the interstates, but they only have one sign for which interstate it is. The other one that has come up sometimes is, i've seen a few people message me about getting the state highways wrong. And several people have messaged me like, ha, ha, like, you got the states backward.