General Description: Liquid anti-icers and de-icers are salt compounds extracted from the Great Salt Lake with added corrosion inhibitors used to prevent or remove the build up of ice and snow on roads.

How They Work: The products are called freezing point depressants, and work to lower the freezing point of moisture, to a surface temperature of 15°F or lower. What's more, they can help prevent the build up of ice and snow and melt existing ice and snow.

Environmental Impacts: Liquid anti-icers and de-icers are much better for the environment than other alternatives including sand and salt. While some sand and salt use is still necessary for CDOT's overall winter maintenance program, increased use of liquids has drastically reduced air pollution associated with sand use and has reduced the amount of sand run-off that endangers roadside plant life as well as the amount of silt that goes into streams, especially at higher elevations.

Impact to Vehicles: Salt products naturally lower the freezing temperature of water, but do have some corrosive properties. Motorists should always wash their vehicles after any snowstorm to remove liquid de-icer residue that may come into contact with your car, just as you always should with salt and sand/salt mixtures. Unlike sand and sand/salt mixtures, however, liquid de-icers will not damage your car's paint job or windshield.

Economics: At $.35 a gallon, the liquid anti-icers and de-icers used by CDOT are the least expensive alternatives to sand and salt on the market. In addition to reducing the need for the less environmentally friendly sand/salt mixture, the application of liquids helps to reduce maintenance costs by lessening the need for plowing and after-storm sweeping.

Usage Trends: In the winter of 1999/2000, the use of liquid anti-icers and de-icers allowed CDOT to reduce its consumption of sand and salt mixtures that contribute to PM10 (particulate matter contributing to the "brown cloud" effect) by 23 percent, or 133,406 tons.

Efficacy: In a comparison of five areas around the Denver metro area, CDOT found that increasing the use of liquid de-icers over a two-year period reduced accidents by an average of 67 percent.