The term "road debris" can mean anything from dust to entire engine blocks[1]. The debris in question here is a metal tow hitch. http://en.wikipedia.org/wiki/R

The term "road debris" can mean anything from dust to entire engine blocks[1]. The debris in question here is a metal tow hitch. http://en.wikipedia.org/wiki/Road_debris#Examples http://en.wikipedia.org/wiki/Road_debris#Examples See my other comment upthread for an example of a gasoline car catching fire because of cardboard boxes.