Around here the term black ice in the news has become a sensationalized term. Every morning now in the winters with temps well established below freezing is coined black ice on the morning news.
I learned of the term black ice 12 years ago when I rode a motorcycle. It was described as spots on the road where ice would be hidden from the sun such as shaded by trees that is nearly invisible to you. Describing ice that forms from a cold ground on an otherwise above freezing temperature day is also a good description. "Black" doesn't derive from what color it is, but is derived from the fact that it is unexpected because the air temperature is not of freezing temperature.
My wife rolled her car this past January from sliding on ice and landing in a ditch on the side of the road when it was 40° out. The air temps rose quickly in the mid morning from about 28° and it started to rain. The ground temperature wasn't warmed up yet and the road was a sheet of ice. As she had left the house and the air temp was 40° and not knowing how quickly the temps had come up, ice on the road was totally unexpected.