My brother was behind a truck carrying vinyl siding and sheets of siding strtaed falling off the back of the truck. He avoided as much as he could but the ones he hit made his car slide like hitting an ice patch.
He pulled up next to the driver and at 65 MPH honking the horn and telling him that his load was falling off the truck. Driver just gave a blank stare in return and sped off. A few miles down the road he saw the truck at a light with an empty bed
I have managed to avoid a ladder spinning towards me while traveling 75 MPH in NM, I did not notice it at first until my wife started screaming. Semi behind me finished it off and luckily did not lose any tires.
Being in NC I have encountered paint barrels, couches, tires, fence posts...