4513.31 Securing loads on vehicles.
(A) No vehicle shall be driven or moved on any highway unless the vehicle is so constructed, loaded, or covered as to prevent any of its load from dropping, sifting, leaking, or otherwise escaping therefrom, except that sand or other substance may be dropped for the purpose of securing traction, or water or other substance may be sprinkled on a roadway in cleaning or maintaining the roadway.
(B) Except for a farm vehicle used to transport agricultural produce or agricultural production materials or a rubbish vehicle in the process of acquiring its load, no vehicle loaded with garbage, swill, cans, bottles, waste paper, ashes, refuse, trash, rubbish, waste, wire, paper, cartons, boxes, glass, solid waste, or any other material of an unsanitary nature that is susceptible to blowing or bouncing from a moving vehicle shall be driven or moved on any highway unless the load is covered with a sufficient cover to prevent the load or any part of the load from spilling onto the highway.
In Ohio at least, vehicles such as dump trucks, construction trailers, landscaping trailers are responsible for covering and/or securing their loads. So, for example, a landscaping company doing 70mph down the highway with an uncovered trailer of mulch blowing every which way would be in violation of said law. Lucky for you, no real damage from blowing mulch around.
Dump trucks/construction trailers are no different. You have mud and rocks that could either be caked onto construction equipment or being hulled in bulk from location to location. At the gravel yards, they have rumble strips the trucks drive over to dislodge any loose material so it falls off there instead of out on the road.
Now out on the road, if debris falls off the truck and hits the ground and then in turn hits your car, guess what? Your fault, you just hit a road hazard. However, if the debris falls off the truck and onto your car, causing damage, guess what? Not your fault. The trick is two-fold though. You need to prove it came off the truck and hit you directly, and you need to prove there was damage.
Fortunately or unfortunately in my case, the dash cam caught a rock falling off the back of the truck onto the spinning tire. The rock then proceeded to fly up into the air and then land at a downward trajectory about six inches to the left of the dash cam. You can see it's entire flight path on it's fateful journey.
Now the adjuster was completely up front and said that in 90% of cases he denies windshield claims like mine for lack of proof. But in my case, you really couldn't ask for a better example of why to have a dash cam. 1080p/45fps was good enough in this case. However, I think 60fps would be better for the future.