Wintry weather in Northern Virginia's I-66
Credit: Leigh Goessl/All rights reserved

Wintry weather in Northern Virginia

What Drivers Should Know About Black Ice

As winter sets in and temperatures begin to dip to freezing levels, dangerous driving conditions typically emerge. One wintry condition motorists often encounter while traveling or commuting is "black ice." In November 2013, hazardous black ice conditions created a massive pileup in Worcester, Mass. involving 65 cars and trucks traveling on I-290. In the accident, 35 people were injured1. Fortunately, no deaths were reported. 

This type of freezing is common in northern regions, however, even in areas that generally have seasonally warmer climates in the winter, there is a chance of a cold snap that comes with precipitation, creating both wet and icy conditions. When black ice forms, there is high potential for disaster, so it is helpful for motorists to know what it is and learn techniques to try and stay safe in case it is encountered when on the road.

What is Black Ice?

Black ice is a transparent thin layer of ice that is often very difficult for motorists to see on pavement, as opposed to normal icy road conditions which are a bit more visible. How Stuff Works suggests in its article it should "really" be referred to as "clear ice."2 However, while black ice is technically clear, its name is derived from its ability to blend in with surroundings, masking its presence to drivers. The reason why it is so hard to see is because there are few air bubbles and motorists often mistake the precipitation as wetness. This makes it extremely dangerous. As a result of its masked appearance, a driver is often unprepared for the skidding that could instantly occur when the tires meet the ice.  

Slushy roads
Credit: Leigh Goessl

A typical icy road

How is Black Ice Formed?

According to Maine's Bureau of General Services, black ice can form under a few different types of conditions. This includes frozen condensation from overnight dew and melted snow that runs across a road and then subsequently freezes. 3 Kristen Rodman, of Accuweather, indicates black ice can also form when temperatures are "32 degrees or below at the surface and rain is falling." 5  Once the rain hits the ground, it freezes, instantly creating slippery conditions.

Rainy conditions occur during (or are followed by), freezing temperatures can also create perilous driving conditions. In addition, black ice tends to be isolated and spotty, so drivers can suddenly come across a patch of it unexpectedly, taking them by surprise. Yet, it might not be present in all "wet" areas of the road. Additionally, the layers of ice are usually so thin, the pavement is completely visible, making it unique to other types of icy road conditions.

Ways to Spot Potential Black Ice

The problem with black ice is drivers are often unable to see it on the road until it is too late. Once a car's tires hits it at the right angle and speed, the tires will typically begin to skid. The State of Maine provides a few tips on what motorists can look for as they are on the road:

  • Pavement that appears to be dark, wet or new asphalt
  • A duller appearance as opposed to other parts of the road
  • Low-lying areas that may have standing water present
  • Bridges and underpasses
  • Roads that do not get sunlight during the day

When temperatures drop below 40 degrees Fahrenheit (4.4 Celsius), drivers should also be cautious of black ice. In any of these conditions, drivers should be aware of a potential icy presence. Normally shady locations are more likely to have invisible icy conditions.

Wintry driving
Credit: Leigh Goessl/All rights reserved

Authorities arrive on the scene of an accident that occurred on an icy/wet I-66

What Drivers Can Do

While black ice is not totally preventable or predictable, there are a few actions you can take to reduce risks. These strategies include:

  • Paying closer attention to the roadway
  • Knowing how your vehicle responds to different weather conditions
  • Understand how your vehicle's braking system works
  • Driving at slower than normal speeds when potential icy conditions exist
  • Always ensure anyone in the car is wearing their seat belt
  • Maintain a safe distance from other motor vehicles
  • Watch vehicles in front of you to see whether they are sliding or giving off water
  • Avoid using cruise control during wintry conditions
  • If you do skid, steer in the direction of the skid

The State of Maine recommends putting the transmission into the neutral position may also help when encountering black ice. 3  It is also a good idea to remember - those "bridge freezes before road" signs are there for a reason -- bridges and overpasses are more likely to freeze first due to cold air being present below and above the road. In contrast, regular roads only are exposed from one side. Additionally, drivers should always keep in mind 4-wheel drive vehicles are not infallible to ice. In the Washington, D.C. area, where there is constant road congestion on both highways and most secondary roads, based on my personal observations, it appears many drivers of all or 4-wheel drive cars seem to think they can rapidly cruise in any type of road conditions.  Wrongful thinking -- while these vehicles do provide better balance, even these cars are not accident-prone on icy roads. No vehicle is infallible to ice.

It is not uncommon for assumptions to be made that black ice-related accidents are caused by careless driving. Additionally, while sometimes negligent driving is the case, actual data seems to suggest many of these accidents cannot be classified as not exercising due care. According to Icy Roads Safety, this is especially true since it often appears without advanced warning. 4 While often accidents occur due to distracted or careless driving, even the most skilled or careful drivers can find themselves suddenly out of control when this type of ice appears on the roadway.

However, being armed with knowledge of both weather conditions and your own vehicle can help reduce the risks associated with this type of wintry weather condition.