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GREENSBORO, N.C. (WGHP) — If snow and ice are in the weather forecast, chances are you are seeing highway department trucks spraying a liquid solution on dry roads.

You’ve heard the term “brining.”

Trucks will be out across the region starting Thursday or Friday to spread brine in anticipation of the arrival of snow on Saturday night and Sunday.

You’ll have to continue to watch WGHP to find out the count and the amount.

But do you really know what brine is or how it works? Neither did we, so we did some research and found these five things to know:

1. What is brine?

There are varying formulas for brine, but the NC Department of Transportation says it’s a solution of water containing roughly 23% salt. Some people throw in magnesium chloride with the salt, but the mixture still comprises 23.3%. NCDOT says it sometimes adds 10% calcium for a post-storm treatment.

2. What does brine do?

The solution when applied correctly can lower the freezing temperature on the road. Typically that is 32 degrees of course – freezing point – but brine can help the precipitation to remain liquid up to about 18 degrees. Some good news is that most forecasts in the lower levels of the Triad have temperatures not falling below the 20s. Brine also helps to prevent snow and ice from bonding with the road’s surface by seeping into cracks and crevices and from snow being compacted by vehicles, which can create ice, NCDOT says.

3. How and when is it applied?

The best case for brining is on a dry road when the temperature is above 18. That can be done about 24 to 48 hours before a storm hits and protect against icing. The application rate varies based on road conditions (temperature and forecast), but the rate can be as little as 40 gallons per mile or as much as 110 gallons.

4. How much does it cost?

Tens of gallons per mile sounds expensive, but NCDOT calculates that brine costs about 15 cents per gallon (as of 2020). NCDOT says the cost to treat a mile of single-lane is about $6. The rock salt that often is added after the snowfall costs about $14.38 for that same area.

5. But what does it do to my vehicle?

Salt is bad for the metal in any vehicle, and brining roads adds to that potential problem. Some of the ingredients can cause acid to form that will eat up that metal. The liquid brine can spray up beneath a car, which typically doesn’t get cleaned except in a car wash. One item to know: If you keep your unwashed car in a colder environment (rather than a warm garage), that will resist the formation of the acid. Experts also suggest not following behind trucks that are spreading brine because the liquid will bounce and get beneath your vehicle. There are products made for removing salt from vehicles.