There are a number of different road designations in the United States, from highways and freeways to interstates and routes, and it can cause some confusion with different laws and regulations.

Ever wondered how the highway and interstate numbers came to be? What do they even mean if they mean anything at all? Behind those numbered shields displayed on the signs is a mathematical logic grid ...

At first glance, the U.S. Interstate Highway system might seem like a logical grid-based masterpiece with a semblance of order behind its numbering system. Odd-numbered interstates run from north to ...