The City of Edmonton plans to keep using an anti-icing agent to clear streets this winter after two years of a pilot project that used calcium chloride on nearly 3,000 kilometres of city roads.
The city released reports Thursday that show the results of the pilot project. Fewer collisions happened in areas where the brine was used, the reports say.
Gord Cebryk, city deputy manager, said the recommended solution is a combination of salt, sand, plowing and blading.
“We’re trying to focus on safety,” Cebryk told media at city hall Thursday. “Our focus on achieving bare pavement is resulting in safer driving conditions.”
Since 2017, the city has been exploring different combinations with the goal of creating safer roads.
“The best way of achieving bare pavement is through the use of a variety of tools depending on the weather conditions,” Cebryk said.
He referenced a study done by the University of Alberta, which shows that during the pilot project collisions went down nearly 20 per cent in areas where the brine was used.
The calcium chloride controversy
Calcium chloride has been controversial with some members of the public, who believe it rusts vehicles, garages and impacts concrete.
The reports say studies done in 2018 and 2019 found that “salt and brine impacts on asphalt and concrete are minimal.”
The city reports include a study on brine corrosion prepared by Corrpro Canada Inc., which said research has been done worldwide to determine the impact of anti-icing and de-icing agents on vehicles and metal infrastructure.
“However, the results of research programs found in literature review have been inconsistent,” the study said.
A memo leaked to media earlier this year, written in June 2018 by engineers, suggested the city’s calcium chloride brine damages roads 20 per cent more than salt alone.
Coun. Andrew Knack said few people likely know that the city has been using calcium chloride for many years, in different amounts.
He noted the reports show there were fewer collisions on roads where the brine was used during the pilot project.
“I don’t know if that’s going to matter right now to a lot of people,” Knack told CBC News Thursday. “There’s been so much conversation around what this may or may not be actually doing to private property, to public infrastructure.”
In the 2018-2019 season, the amount of calcium chloride the city used was “significantly lower” compared to 2017-2018, while the amount of salt and sand was slightly higher due to extreme weather.
Cebryk said the city used the brine only twice last winter.
Calcium chloride brine contains a corrosion inhibitor to offset the potential impacts on metal and concrete, Knack said.
“It may not be causing the issue that people think it is. It could be — if we assume that there are in fact impacts— the level of salt that we use, particularly this last year in comparison to the level of salt the city had used in the past.”
The province uses a calcium chloride on highways like Anthony Henday Drive.
Knack noted that the brine solution has made a positive difference at seniors’ complexes and on sidewalks.
He said other jurisdictions that use brine have accepted that any impact is “outweighed by the safety benefits.”
Councillors are scheduled to discuss the reports and the city’s snow and ice policy at a community and public services committee meeting on Sept. 4.