Buzz
Ever seen the strange white streaks on the pavement just before a winter storm and wondered what they are? They aren’t a trick of the light; they’re deliberately applied for a good reason: to keep you safe.
This process is known as anti-icing, a technique designed to improve road safety in winter conditions. Typically, a liquid chemical like magnesium chloride is used to lower the freezing point of water. (Brine solutions made with sodium chloride and water, or calcium chloride and water, are common alternatives.) Once applied to a road, it helps prevent snow and ice from adhering to the surface, making it safer for drivers [PDF].
According to the Minnesota Stormwater Manual, anti-icing is “like frying eggs: grease the pan and the eggs come out easily with no mess to clean up. Like greasing the frying pan, the goal of anti-icing is to prevent snow from bonding with the road.”
For any anti-icing strategy to be effective, timing is crucial. This method is most effective just before rain, sleet, or snow begins to fall. It’s a sharp, proactive contrast to de-icing, which essentially works in reverse (even though the two terms sound similar).
De-icing focuses on breaking the bond after it has formed between snow or ice and the pavement. This method is more reactive and commonly used for winter maintenance. It typically involves applying pre-wetted rock salt [PDF] to roads after a storm to break up the bond between snow and pavement. If you see snowplows in action during a storm, you might witness this de-icing process firsthand.
Although de-icing is the more common method used on our roads, experts say it’s actually more costly than anti-icing. Anti-icing is considered more affordable because it can be done during regular working hours in non-stormy weather, reducing the need for overtime. It also speeds up post-storm cleanups as the treatment can last for days, keeping the streets safer even if a blizzard doesn't hit right away. Additionally, it prevents snow and ice from bonding to the roads in the first place.
Supporters of anti-icing also argue that it is better for the environment since it uses fewer chemicals and results in less silt buildup, as well as reduced harmful runoff into stormwater systems. However, the brine solutions used for anti-icing may not always be ideal for your car, as the salt crystals often accumulate on a vehicle’s undercarriage, potentially causing corrosion and rust.
To minimize this risk, experts recommend regularly washing your car during the winter months, with particular attention to the undercarriage (which you should consider cleaning every 10 days or so) to avoid buildup and reduce the chance of corrosion.
