Everyone knows that highway signs aren't supposed to bounce like they just remembered the lyrics to "Jump Around" by House of Pain. But this particular sign across a highway in Calgary, Alberta, Canada doesn't care about your so-called common knowledge.A storm that brought some serious wind sent this crossbar into gyrations so severe that cars began changing lanes to get out of the way. And if you watch all the way to the end of the short video, you'll see they had good reason. Scroll down to watch the scary stuff.