Road brine is a fairly new development in road safety. For years highway crews have scraped the snow and ice off of roads after a winter storm starts. But now state and local transportation departments have been using a method called road brining.
The difference is that road brine is applied before the precipitation falls. This method makes roads much safer.
Salt is mixed with water to make a solution that is about 1/4 salt and 3/4 water. Sometimes a transportation department will add magnesium chloride into the mixture and sometimes calcium. Some transportation departments also mix brine with sand.
In some cases, a transportation department will mix the salt brine with organic substances like whey or ground up sugar beets. These organic substances make the brine stick to the road longer and are more effective for longer periods of time.
The road brine is applied before the snow and ice forms by using a tanker truck that is equipped with pumps and sprays nozzles. As a side benefit, using road brine saves a lot of money for state and local transportation departments. But there are many reasons why road brine is safer for roads.
Why it’s Safer
In the first place, road brine actually stays on the road. Riding behind a salt truck people notice that the rock salt bounces around all over the place. Up to 30 to 40% of the salt usually just bounces off to the side of the road. Having the salt mixed with water makes it stick to the road and be much more effective.
Another reason why road brine is safer for roads is that having salt and water mixed together reduces the freezing point of the precipitation. If a highway is already frozen then the ice or the snow will immediately freeze when it hits the pavement.
If the road has been treated with brine ahead of time, then the freezing point is no longer 32 degrees. Now the ice and snow won’t freeze until the temperature is -6 degrees. So it is clear that treating the road before the precipitation starts will keep the road from getting slick. Very few places regularly have temperatures that low. Having the brine on the road before the temperatures go below 32 degrees also keeps frost from forming on the road surface. Once the ice and snow have bonded to the road surface, it is much harder to get the payment clear.
Another way brine is safer is the fact that it works much more quickly than straight salt. If there is brine on the road, then when the very first snowflakes hit the pavement, they melt immediately. Even when there is significant deep snowfall, the brine on the road makes it easier for the snowplow to scrape down to the pavement.
Avoiding black ice is an important consideration in keeping winter highways safe. Salt brine is particularly helpful in getting rid of black ice. If roads are treated frequently during an ice storm, brine can keep the black ice from even forming in the first place.