When it comes to keeping snow and especially ice off the highways, the Colorado Department of Transportation uses several chemicals to help. Deicers are used to break the bond of already existing snow and ice, dissolve downward and penetrate until they reach the pavement. Deicers melt the ice and snow so they can be easily removed by the plows and are not necessarily intended to clear all the ice and snow off the road.

CDOT uses three different liquid deicers and two solid deicers.

"We use the dry and liquid products together, in conjunction with each other. The only thing we are concerned with when applying the liquid is the temperature and switch over when the temperatures drop below 16 degrees," said Mark Carrillo, CDOT supervisor. "We can apply these products throughout the storm. Just like everything else when the temperatures get too cold you get the thaw and freeze cycle but it works pretty well for the whole storm."

The three liquids include magnesium chloride solution that is about 30 percent solution. It is effective when road temperatures are between 32 degrees and 16 degrees. When the temperature is much lower CDOT uses Caliber 1000, a cold temperature magnesium chloride. The product includes a corn bi-product to lower the freezing point and is effective from 16 degrees to zero degrees. The third product is called Apex. It is a multi-temperature liquid that is used in the automatic deicing systems that are in place on several bridges around metro Denver. It is effective at temperatures to 4 degrees below zero.

"Reading the surface temperature of the roads is very important to knowing when to apply the liquid," said Roy Smith, CDOT's acting maintenance superintendant. "Each plow contains a temperature sensor that helps each driver determine which product to use. They frequently verify the ambient and pavement temperature throughout the snow removal process."

The two solid deicers are basically road salt mined from Utah. The new product this year is called North American Salt. It looks pure white like chunky table salt and it comes out of the Great Salt Lake. The company collects the lake water and then evaporates out the liquid and is left with the salt. CDOT says the mix works great and is cheaper than Ice Slicer, which is basically the same product as the North American Salt but it is mined from the earth not from the lake. The product looks like a salt sand mix just because it has a little bit of earth but it is not a true mix.

CDOT says it does use a salt/sand mix in many parts of the state but not in metro Denver because of the air pollution regulations. CDOT does not pre-treat highways in advance of a storm, but rather starts to apply liquid deicers once the snow starts to fall.

CDOT's deicer specifications area set by Dr. William Lewis, University of Colorado professor and water quality expert.