DECEMBER 2023
What’s with that liquid being applied to the roads?
Throughout the fall and winter, we get regular inquiries at the City asking, “What’s that liquid you sprayed on the roads?” Or, “I thought the City doesn’t use salt?” I even received a call from a concerned resident who thought a massive fuel spill covered nearly the entire length of Olympic View Drive. Fortunately, that was not the case, but I started thinking, if a few residents are wondering what those lines of liquid are, then there must be others and we should get everyone informed!
Those lines or
bands of liquid that you can clearly see on a dry day are an indication that a
freeze or snow event is likely to occur and evidence that your City of Edmonds
Public Works maintenance team is preparing for such conditions. Every winter the Public Works crews ready our
streets for the dip in temperatures by applying the anti-icing, pretreatment,
and de-icing agent known as calcium
magnesium acetate (CMA). Applied via
a truck equipped with a reservoir and spray nozzles (hence the lines), this
multi-purpose solution has many of the same benefits as the traditional use of
salt. Edmonds is committed to providing a low-corrosive and more environmentally
friendly form of road safety, so CMA
has become our go to frosty weather treatment for the last 20 plus years.
Coating the high
traffic, busy intersections, and steeped sloped surfaces with a proper CMA application prior
to the wintery conditions prevents the snow/ice from bonding with the road
surface to avoid slick, unsafe conditions.
City of Edmonds snow plows can also remove more snow from the streets
with each pass by creating a reduced bond between the snow and roadway. This stops the formation of ice before the
actual storm begins. The unique properties of CMA interferes with particles’ ability to adhere to each other
and the road surface by tying up the moisture melted and reducing the early ice
formation. Because of this, CMA is often referred to as an ‘anti-ice’
treatment rather than a traditional ‘deicer’ application such as road salt (NaCl). However, the unique performance
characteristics of CMA means it can also do its fair share of deicing too - during
the record breaking snows the past few years, our plows have used a CMA/sand mixture with success to help
aid with the breakup and removal, clearing arterials considerably faster than
without it.
Sadly, there
really is no way to eliminate risk to the environment when we’re talking about
snow/ice removal. But offering a safer alternative
to exclusively using road salt, which has proven to be both corrosive to
vehicles and damaging to infrastructure, can provide the lowest toxicity,
biodegradable alternative which performs well and keeps our roads open and
residents safe. CMA biodegrades into natural
byproducts
CO2 and H2O, it doesn’t contain
urea, chloride, or nitrogen, and has minimal impact on stormwater discharges. It is also perfectly safe for asphalt and
concrete. One drawback is that it requires reapplication between rains by our
Public Works crew. As a benign anti-icing agent, it’s a shortcoming that we can
happily live with.
So, when you see
the CMA spray vehicle this
winter, or the plow/sanding trucks spreading a mixture of sand and CMA, please afford them a little
extra space. Our snow and ice
professionals typically need a buffer to work safely and allow space on all
sides to spray thoroughly and properly.
While a little CMA on
your SUV is not the worst thing in the world, we do prefer to keep it on the
road surface for your benefit. Stay safe and happy winter driving!