acording to federal law (carring a cdl which is nationwide) it is interstate or intra state you are responsible for any damage caused(at least that was what I was told by the MTA, they do the enforcment in michigan but they said this was federal). your vehicle is supposed to be tarped(some states do not enforce it on local roads but if they are on a state or us highway) if it is not your load has to be at least 1 foot below the sideboards. tailgate cannot be dropping material in the roadway(all violations) i won a case with a dump truck(gravel train)who had a how is my driving sign. i have a 50 dollar decuctable on my windshield and had 3 good size chips, called them after got a police report with their truck# and plate info and they paid ,it happened outside nashville