What is black ice? How it forms and why it's so dangerous

Black ice is a thin, nearly invisible layer of ice that forms when wet roads refreeze after dark, making bridges, overpasses and shaded roads dangerously slick. It gets its name because it takes on the dark color of the pavement beneath it, which is exactly why drivers don't see it until it's too late. Knowing where it forms and what to do when you hit it could save your life.

MORE: Heat's on and your sleep suffers: ideal bedroom humidity in winter