Tired

What a day. Today I was driving under an underpass while a construction crew worked on the underside of a bridge. All of a sudden, something fell from the bridge, which I promptly ran over (it was pretty black in there). As you can see from the following picture, it wasn't a small item that fell down. My guess is a hammer. What's your guess?

All in all, a bad day. Maybe "The Office" will rescue me.