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Anti-Icing

Evaluation of a New Anti-Icing Substance

During the winters of 1996-1998, a new liquid anti-icing agent was introduced in various regions of BC. The chemicals involved are environmentally safer and cost-effective. A significant reduction in crash-related claims was recorded during their use. BC continues to lead the country in researching this proactive winter maintenance tool.

Have trouble skidding and sliding in the winter? Do you cringe every time you see the salt truck go by, thinking of the holes it will eat in your vehicle, remembering the plants and animals the salt will affect when it washes off into the ditches? Do you have stone chips in your windshield as a reminder of the last snowstorm when the gravel truck went by? Ever been involved in a crash because of "black ice" on the road? Well, take heart. Research is currently underway to find better ways to keep our roads safer.

The way it's always been:

ICBC is taking a serious look at winter road safety methods. If you spend any time watching a major roadway in BC during the winter, you will witness a common scenario.

  • During a snowfall, a plow will pass by to scrape most of the accumulated snow off the road surface.
  • Shortly after, heavy trucks laden with salt, sand or gravel will follow, throwing large amounts of these substances onto the road.
  • If the snow continues, another plow passes by, scraping away the new snow and whatever that truck had just applied.
  • Another truck arrives to re-apply what the plow has just scraped away the scenario repeats itself over and over, until the weather changes.
A new approach:

If you live in Kamloops, though, you may have witnessed a different scene in the past few years. Just before a winter storm, you may have seen what looked like a water truck, spraying the road surface. Expecting the road to turn into a sheet of ice, you would have been surprised to discover that instead, the roadway remained free of snow buildup. The solution being sprayed on the road was not water, but a new anti-icing liquid currently being tested by ICBC.

Two methods of ice control

Since 1996, ICBC has tested two main methods of ice control known as pre-wetting and anti-icing.

  • In the pre-wetting process, liquid chemicals are added to existing salt and sand before they are spread on the road. This helps reduce the ice build-up, and decreases the amount of salt and aggregate needed.
  • In the anti-icing process, a liquid chemical is applied to the bare road at a specific time before an expected snowfall. It begins melting snow and ice immediately to prevent ice from bonding to the pavement.

Do Anti-icers Work?

While many North American agencies have reported fewer collisions when anti-icers were used, none have reported how large these benefits actually are.

  • ICBC Corporate Research compared data collected from the Kamloops study area with records from the previous 10 years.
  • The study showed that the average number of crashes on days with snow or ice was 8% lower than expected during the study period (when the anti-icing agent was used) than during the ten years prior (when no anti-icing agent was used).
  • From the data, it was estimated that the agent prevented 285-306 crashes over the three-year period, or a saving of 95-102 crashes per year.
How Safe are Anti-icing Chemicals?

Traditional salt used on icy roads is made up of sodium chloride.

  • Depending on factors such as soil permeability and slope of the land, the sodium and chloride ions can be washed towards the roots of trees and plants.
  • These ions build up in the twigs and leaves of trees, and may become toxic.
  • Extra ions in the soil may also interfere with a plant's ability to absorb moisture or other necessary nutrients.
  • With certain species of vegetation, the results can be very serious. In the early 1970's for example, New Hampshire suffered the loss of 14,000 trees along 3700 miles of salt-treated highways.

In contrast, liquid anti-icers contain magnesium chloride or calcium chloride.

  • Magnesium and calcium are minerals essential for plant growth.They are found naturally in soil and water, and are tolerated in high levels by most plants.
  • In Finland, studies showed that reindeer are not attracted to magnesium and calcium as they are to the sodium in road salt.
Recent research

Few complete research studies have been done on the environmental effects of liquid anti-icers. ICBC commissioned Levelton Engineering Ltd. to perform extensive research and laboratory toxicity testing on all potential chemical de-icers. Levelton's March 1999 report concluded, "that applications at recommended rates for anti-icing should pose very little risk to vertebrates, invertebrates or plants."

Effects on cars

Anti-icing chemicals have also proven to have fewer negative effects on automobiles.

  • Magnesium and calcium chlorides are less corrosive than sodium.
  • The anti-icing solution being used also contains an organic corrosion inhibitor, so does not contribute to vehicle rusting.
  • The use of anti-icing chemicals also significantly reduces the amount of sand and gravel on the roads.
  • Loose gravel applied for traction during the winter causes stone chips and cracked windshields after the winter season has passed.

Areas in North America where anti-icing chemicals are used report a 10% to 75% reduction in the use of sand and aggregate.

  • For example, the City of Kamloops said they use 50% less sand, and the City of Kelowna reported they use 40% less.
In the Future

A variety of anti-icing chemicals have been used for more than 20 years in Europe, and for about 9 years in the United States. In Canada, some provinces have tested pre-wetting agents, but consistent use of anti-icers has not yet been implemented.

ICBC piloted the use of liquid anti-icers in Kamloops during the winter of 1995/96. Vernon (in partnership with the Ministry of Transportation and Highways) and Kelowna were added to the project in 1998/99. Since then, the project has been expanded to include additional communities across the province:

Abbotsford

Fort St. John

Prince George

Sparwood

Armstrong

Keremeos

Quesnel

Vancouver

Cranbrook

Nanaimo

Revelstoke

Williams Lake

Dawson Creek

Nelson

Salmon Arm

 

 

ICBC provided $1.6 million in grants and training for the testing and use of liquid anti-icers.

  • As of 2000, 85% of the highway contractors in the province were using pre-wetting, anti-icing or both methods to reduce slippery road conditions.

Financial benefits of the program in the form of reduced claims are expected to be two to five times the investment in the study. Potential benefits of reduced injuries and reduced environmental impacts can be considered priceless.

Additional information: Link to http://www.wsdot.wa.gov/partners/pns/default.htm

 

 

 
 
 

02.12.04