Here's a link to a story from our area today. It appears there was a Dump Truck traveling at highway speeds with the box up at 5 o'clock this morning when he hit a bridge across one of our expressways. You might have to sit through a commercial before the video starts. It looks like the box became jammed under the bridge and tore free of the truck, at Highway Speed!!
http://www.wbay.com/story/22483801/2013/06/03/dump-truck-hits-pedestrian-bridge-in-appleton
http://www.wbay.com/story/22483801/2013/06/03/dump-truck-hits-pedestrian-bridge-in-appleton