The Ontario Ministry of the Environment (MTO), like most cutting-edge snowfighters in North America, has moved strongly into using liquids in its winter maintenance functions. Among the motivations: reducing the amount of salt used to keep the roadways clear and safe. Unlike many agencies, however, MTO determined to document the benefits achieved by adopting pre-wetting of rock salt and use of salt brine applied directly to roadways ("direct liquid application" or DLA). MTO's chef technology researcher Max Perchanok, reported the agency's findings to the Ontario Good Roads Association's annual Snow and Ice Colloquium yesterday.

MTO's prediction in adopting pre-wetting was that they could achieve the same level of service and save about a third of the salt they applied. An early 1995-99 test using 5% brine achieved a 23% salt reduction and a follow-up study in 2002-03 found that increasing the brine component to 7-15% achieved salt savings of 18% to 40%. As a result, 99% of MTO's (mostly-contractor-operated) fleet now is equipped for pre-wetting. Adoption of pre-wetting was confirmed in another study in 2004-2006 which found an 8% to 30% reduction in granular salt usage.

MTO also moved towards DLA with forecast salt savings of 20% to 30% and all its contractors incorporated DLA into their operations by the wnter of 2005-2006. Confirmatory research, however produced disparate results ranging from no salt savings to savings of 50%. MTO has concluded that it has achieved overall salt reduction, but "salt savings are not confirmed" because of the "highly variable results."

Most surpriing to MTO was the corollary examination of the outcomes of using liquids. Using liquids has allowed the agency to reduce the frequency of salt applications by 17% to 33%. A study in Kenora determined that using liquids reduced the time to achieve bare pavement from an average of 20 hours in 2000 to an average of only 2 hours in 2003 when DLA was implemented. "The level of service improved," MTO concludes. Moreover, a study in Waterloo found a dramatic improvment in crash prevention. Anti-icing with liquids was found far more effective than using pre-wet salt; the study, however, identified only marginal safety improvements in using pre-wet salt which is directly counter to an established relationship in the published research literature that shows performing winter maintenance service slashes crash rates by 85% and injuries by 88%.

In sum, MTO found using liquids improved their operations and, particularly the safety of Ontario highways, achieving a higher level of service and delivering on predicted salt savings, though this latter conclusion was supported only with inconsistent data.