We're gonna admit something right now. We've been driving for a decade and a half, and we didn't know about the gas-pump arrow until two years ago. We always thought it was just some graphical element in our old Legend's fuel gauge. Laugh if you want, but in case, like us, you're duncey, our hyper-efficient sister at Lifehacker has a primer on the gas-pump arrow, as well as some tidbits about interstate highway numbering. Check it.