Why are plows not putting salt on the roads?

Now three days after the recent snow, area roads are still snow covered and slippery and some areas of roads that did get cleared, have since iced over which has some area residents wondering why the county and city hasn’t applied salt to melt the ice and snow. The truth is that salt only works down to a temperature around 20 degrees.

Kind of.

It technically will melt down to -6 degrees, but its not as easy as just spreading salt like normal. It takes more salt to melt ice at colder temperatures. At 30 degrees, one pound of salt will melt about 46 pounds of ice. At 20 degrees, one pound of salt will only melt about nine pounds of ice. And at 0, one pound of salt will only melt about four pounds of ice. So the colder it gets, the more salt is needed to provide a given amount of melting action. It also takes longer for the salt to work at colder temperatures, so it would take 10 times more salt to eat away at the ice at these temperatures and that just isn’t practical, much less the effect that much salt would have on the vegetation near the roads and the metal on our cars.

So we are stuck with just dealing with the snow covered roads until it warms, unless a municipality has sand to spread which can help with traction.

Then there is the ice that forms on dry roads even though it seems there was no ice causing weather. This Black ice as it’s called, can form a few different ways.
One is as the sun shines during a certain part of the day, the insolation will melt a little bit of snow near the roadways even though its very cold. Then this bit of moisture will refreeze as ice when the sun either gets covered by clouds or sets, leaving behind a perfectly smooth area of ice on the road.

The real problem is, it’s not uniform over the whole road. A driver can be driving on clear, dry roads for miles, with the assumption the road will continue to be dry, but then hit a patch of ice on a curve and lose control and crash. Black ice gets its transparency by being thin and containing few air bubbles, allowing it to blend in with the pavement and appear “black.” The ice itself is not black, but visually transparent, allowing the often black road below to be seen through it.

The Department of Transportation says to look ahead on the road for any slight discoloration that could be ice, and if you hit a patch of ice and begin to slide, take your foot off the gas but don’t break. If your car does begin to skid on the ice, turn the wheel in the direction of the skid.