What does "black ice" refer to?

"Black ice" refers to a clear, thin layer of ice that forms on roadways, often making it nearly invisible to drivers. This type of ice typically appears on asphalt, which is dark in color, leading to the term "black ice." It is particularly hazardous because it can create very slippery conditions without any visual indications of danger. Drivers may not realize the ice is present until they experience a loss of traction, which is why understanding the nature of black ice is critical for safe driving, especially during colder weather conditions.

The other options describe different phenomena that are not related to the concept of black ice. Thick ice covering the road can be seen easily and poses a different set of challenges. Frost on windshields relates to moisture freezing on glass surfaces rather than on the pavement where vehicles travel. Roads treated with de-icer do not involve black ice, as the treatment is meant to prevent icing conditions, enhancing safety. Understanding what black ice is allows drivers to take precautions in potentially dangerous driving situations.