Black ice forms when rain hits freezing cold pavement. If sleet or freezing rain is in the forecast, be extra careful on the road. If there's been significant snow melt during the day, black ice can form at night when temperatures drop. Dry pavement with shiny patches are sure signs of black ice.
Avoid shady areas where ice may not have yet thawed. Roads running under overpasses and bridges are also susceptible to black-ice formation, since the sun can't evaporate water as efficiently.
What should you do when you hit black ice? First step is to stay calm. Don't oversteer or brake hard. Pump brakes and uses small corrections to keep from losing control. Avoid using cruise control when conditions may be icy, since cruise control can actually accelerate your car when the tires lose traction. Drive smoothly and slowly when the weather is bad, and if ice is particularly prevalent, skip going out altogether and stay home.