Many years ago I was northbound in the left lane of the Garden State Parkway in New Jersey at about exit 160. An old, beat-up pickup truck in the right lane about a hundred feet ahead of me lost the home-made, plywood camper out of the back of the bed. It flew up in the air, probably about twenty feet, and just splintered when it hit the ground, just about right next to me. I never even slowed down. Needless to say, there was widespread panic in the road behind me. As I drove on over the rise, it appeared that everyone was able to stop safely.
Another time, on US 46, again in New Jersey, a small (about 12 - 13 foot) boat came off the trailer and skidded to a stop just off the right side of the road. I didn't stop then either.
I've seen a lot of thing in almost two million miles.
Russ