I was driving to work on I-595 Wednesday (yes I live that far away from the station!)...and saw that the West bound lanes were closed. The East bound lanes, where I was traveling, were slow and go thanks to the "gawker" effect.
Apparently, a dump truck went vertical and crashed into the overhead sign. It was all caught on dash cam. See the video below. Coincidentally, I too have a dash cam, but my view was not as good as this guy's since I was going the other way. I grabbed a still frame from my cam when they were trying to haul the dump truck away. At the time I thought: "what could possibly smash the back end of a dump truck?". Apparently it's own weight smashing down on the road! Check out the vid and my picture from the other lane below.