Abstract Manager

Updated Findings from Pilot Testing of Calcium Chloride De-icer at Very Low Temperatures in Northern Ontario

Andrew Alkins, MTO, Max Perchanok, WSP Canada

Snow and ice control on North American highways is highly dependent on the use of rock salt.  Salt is generally effective at temperatures as low as -10 ^oC to -18^oC.  Lower temperatures occur frequently and for extended periods in Northern Ontario, resulting in higher accident risk, reduced travel speeds and increased frequency of road closures.  The Ontario Ministry of Transportation embarked on a pilot test of calcium chloride de-icer as an alternative to rock salt to restore clear roads at cold temperatures. 

The pilot test involved application of rock salt in a highway section designated as the control or baseline condition, and simultaneous application of calcium chloride deicer in a similar and adjacent section designated as the test condition.  Weather and road conditions were measured at regular intervals from the start of snow-covered conditions until restoration of substantially bare pavement in each section, during each storm event.  Weather and traffic conditions were demonstrated to be similar in both sections during the test events, with snow cover condition being the primary uncontrolled variable.

A first season of field testing in 2024-25, provided encouraging results but insufficient test cases to support a reliable conclusion.  A second field season in winter 2025-26, acquired additional tests and used simultaneous data acquisition from multiple technologies, providing redundancy in case the extreme weather rendered one inoperative.  An additional step was added to the analysis using a previously developed prediction model to estimate the change in direct costs and road-user financial benefits associated with the use of calcium chloride.   The benefit:cost approach provided the Ministry with objective data with which to formulate future contract guidelines.

The pilot testing and analysis process used in this study concluded with a uniquely formalized and cost-effective approach to future field trials of winter maintenance equipment and materials.