Pavement Failure

This evening an electric freeway sign warned us of "Pavement Failure" ahead. Fortunately our exit came shortly before the impending hazard, but now I'm left musing on the nature of the narrowly averted fate. As far as definitions go, I'm a little fuzzy on the meaning of "Pavement Failure." Is the Tacoma Narrows Bridge Disaster of 1940 an instance of pavement failure?




Or perhaps the sign was meant to warn us that somewhere down the line, the freeway had melted into a large pool of bubbling tar. Such a sign might have spared the lives of countless mammoths and sabre-toothed tigers in Pleistocene L.A.

A gigantic sinkhole? A crack? Have the white lines worn off the road?

"Pavement Failure" is a little too vague for my taste, only slightly better than "Something dangerous ahead."