I was driving from Ste Genevieve, Missouri north towards Chicago last week. After being on the road for an hour or so I heard a weird but forceful thud. Since there was no one in the immediate area, I knew it was not an accident but it was definitely something serious.
I tried the remotely moving my side view mirrors to see if there were any dents on the car but they showed nothing. Occasionally when I crossed the reflectors that are embedded in the road surface I would hear another odd sound, as if a part of the car had come loose and was moving. Still I saw nothing. There was too much traffic to pull over, so I decided that unless it interfered with my driving, I would check it out when I stopped.
So, just over the state line into Illinois I pulled into a rest stop, for, well, a rest. I almost forgot about looking for the damage when I returned but fortunately as I approached the car I looked at the painted surfaces and a little of the undercarriage. There it was. A mangled piece of metal that seemed to be originally about a foot long; now in a tangled mess jammed up in between the frame of the car and the back wheel well.
If this thing had hit tire instead of the frame I think I would have had some serious trouble!