It's referred to as black ice since it's clear and becomes almost invisible against the black asphalt of a road. This thin layer is very dangerous because you probably won't see it in advance and may skid, take much longer to brake and find your vehicle much more difficult to control.
When and where does black ice form?
Black ice is more likely to form around dawn and in the late evening because temperatures are often at their lowest then.
Shaded sections of road are prone to forming black ice because they don't receive much sunlight, which can warm and melt the ice. Bridges and overpasses can also quickly form black ice since they're surrounded by cold air above and below, so they freeze more quickly.
Back roads that don't see much traffic area also more prone to black ice formation. That's because friction from traffic warms the road, so roadways that don't have much traffic are more likely to ice over.
How should you drive in freezing temperatures?
Before you start driving, check your driveway and look at the road as best you can. If you see darker spots, which may look more duller or shinier than their surroundings, it could be black ice.
Even if you don't see any, that's no guarantee, however, since road conditions can vary widely. It pays to stay alert when temperatures are at freezing or below, particularly when you're driving on potential problem areas such as shady roads or bridges.
Don't use cruise control, since you may need to slow down or make other adjustments. It can also cause your car to accelerate in a skid as your cruise control tries to maintain a constant speed, and this can make it much more difficult to control your vehicle.
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Be aware of the cars in front of you, and if the pavement looks wet, check to see if they're leaving tracks or are kicking up water. If they're not, it could be a sign that the pavement is actually iced over, resulting in black ice roads.
Also avoid unnecessarily changing lanes, where you could hit black ice between lanes. Leave enough room between you and the car in front of you so you can have adequate time to stop if the car in front of you starts to fishtail. And if it's your vehicle that hits black ice, it will take you about nine times longer to stop under these circumstances than it takes on dry pavement, according to georgia.gov.
CLEARING ROADS--February 17, 2015 Atlanta: GDOT crews spread their winter mix across the southbound connector just after 17th Street on Tuesday, Feb. 17, 2015. Officials closed their emergency operations center Tuesday after the threat of ice on metro Atlanta’s interstates and state routes no longer posed a danger to travelers “Everything looks good, roads are clear,” said Natalie Dale, a spokeswoman for the Georgia Department of Transportation. “We were really fortunate given the amount of rain we got and the dropping temperatures that we were able to keep the roads free of ice. We had a relatively incident-free morning.” The gusty winds were a double-edged sword, helping to dry up wet patches on roads but knocking down ice-laden trees and power lines, especially in northeast Georgia. Metro Atlanta was largely spared from dire predictions of black ice, with just a few icy spots that were quickly remedied. No major accidents occurred. About 188,000 customers lost power in North Georgia between the state’s largest utility, Georgia Power, and Georgia’s Electric Membership Cooperatives, according to data released at about 9:45 a.m. JOHN SPINK/JSPINK@AJC.COM
Credit: JOHN SPINK / AJC
Credit: JOHN SPINK / AJC
What if you hit black ice?
If you do happen to hit a patch of black ice, use the following tips:
Avoid braking and instead ease off of the accelerator and steer in the direction you want the front of your car to go in. Don't overcorrect if your vehicle starts to slide.
If you have antilock brakes, don't pump your brakes. If you're driving a vehicle without antilock brakes, keep your heel on the floor and use firm pressure on the brake.
Sources: AJC.com, cars.com, Georgia.gov and accuweather.com.