Black ice can be caused by
- water freezing on the road ✓
- snow getting very dirty and hard to see
- hard packed snow in shady areas
- several layers of snow
Answer: A. water freezing on the road
Black ice is caused by water freezing on the road surface.
Why this is the answer
The handbook says black ice forms when moisture freezes on the road. It also notes you usually can't spot it, but shiny black asphalt instead of gray-white is a clue to be suspicious. Since the passage ties black ice directly to freezing moisture, the choice about water freezing on the road matches the handbook's explanation.
Why the other answers are wrong
- B. snow getting very dirty and hard to see — Dirty, hard-to-see snow is a visibility problem, and the handbook does not list it as a cause of black ice.
- C. hard packed snow in shady areas — Hard packed snow in shady areas describes snow that lingers in shade, not the freezing moisture that makes black ice.
- D. several layers of snow — Layers of snow are not mentioned as a cause; the handbook points to moisture freezing on the road surface.
Remember it
If the asphalt looks shiny and black rather than gray-white, suspect black ice.