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. 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.
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.