爱城计划在今年冬天采用新方法防止公路结冰
原始发布日期： 2017-06-30 发布者：玉山字变大 字变小
 The truck used to apply anti-icing solution during a pilot project on some of Edmonton's arterial roads this winter. This winter, the city doesn't need a made-in-Edmonton solution, say officials tasked with improving the city's decades-old winter road maintenance policy. "Sometimes, OK, we're different," said deputy city manager Doug Jones. "But snow and ice is snow and ice." Edmonton's new approach will lean on a solution most other winter cities have already adopted — anti-icing. Jones outlined the plan in an interview Thursday. It's going to council's community services committee next week. What is anti-icing? Anti-icing is a technique that sprays liquid calcium chloride — a salt mined in northern Saskatchewan — on the road 12 to 24 hours before a snowfall. It works like Pam on a cookie sheet, preventing ice from bonding with the pavement down to temperatures of minus 29 C, said Jones. That means plows are more effective clearing the snow during the storm and remaining flakes are likely to melt. What does Edmonton do now? Edmonton uses sand on its roads, with about two per cent salt to keep the sand from clumping, said Jones. That creates poor air quality as cars crush the sand into a fine dust. It's also relatively ineffective, with cars quickly pushing sand to the side of the road in high-traffic locations. Edmonton applies sand during the storm, then plows, getting main roads to bare pavement within 48 hours. But that's a long time and plowing leaves an icy sheen at intersections, said Jones. A second spot application of liquid calcium chloride would eliminate that, preventing ice for up to two days. Getting main roads to bare pavement in 12 hours is possible, he said. "I'm hopeful we can do better than that, all within the same budget." Last winter's pilot project found anti-icing increased friction and resulted in bare pavement on roads like the Yellowhead Trail. This year, the city will scale up as quickly as available equipment allows. What about residential roads, sidewalks and bike paths? A 2015 study by the Western Transportation Institute did a cost-benefit analysis for sand versus calcium chloride, said Jones, including the research in his file to council. The benefit ratio for calcium chloride was 17 times higher. If that holds true for Edmonton, "we should be able to take that same pool of money and reallocate it around the city," said Jones. His team will develop plans for those aspects of snow clearing as they see how much money the anti-icing program will save. Why hasn't Edmonton done this already? "We just haven't revisited our practices for a while," said Jones, who started with the city last September. He became a believer last April when studies presented at the American Public Works Associations' Snow Conference in Iowa found 90 per cent of the municipalities surveyed were already using it. "There will be people who are concerned about the chlorides, but there's no perfect product," he said. "If your first focus is safety, you can't depend on sand alone. Salt isn't the answer because you'll use way too much of it. (This will) minimize that impact." The four pillars of the new policy would be safety, environmental impact, financial cost and social impacts like productivity and mobility. Sensors in the drainage system will monitor run-off for impacts, and Jones hopes to see storm-related collisions decrease. estolte@postmedia.com twitter.com/estolte |