What is That Green Stuff They are Putting on the Roads?

February 24, 2010

This is the time of year when spring fever begins to set in and it feels as if the winter season is never going to end. In fact, the month of March has brought some of the biggest winter storms contained in our state’s record books, including the “blizzard of 1993” that brought nearly two feet of snow to most portions of Connecticut. While such weather would be welcomed by our friends at the local ski resorts, many of us are ready for the warmer temperatures to set in.

Another group of people happy to see the winter weather stick around are those who treat and remove snow from our roadways. They work around the clock during winter storms to make sure our roads and highways are as safe as they possibly can be during adverse conditions. And while the responsibilities of snow and ice removal haven’t changed all that much over the years, what is used to treat the roads has changed.

For the last couple of years now the Connecticut Department of Transportation (DOT) has been using different products to treat and pre-treat our state’s roads and bridges during the winter months. The most notable change is that the DOT no longer uses sand to treat slick roads. What’s notable about that? Well for one thing roads, and therefore cars, are generally cleaner because the brown residue left by the sand has been replaced with a more environmentally friendly solution.

According to the DOT, sand once used for snow and ice operations negatively impacts the environment due to “its tendency to migrate” with surface water. They also claim that in the past, too much time and money had to be expended to pick up and dispose of the sand that was put down. With the new technology, this is no longer necessary.

So what are Connecticut’s roads being treated with?

In 2006, the DOT introduced a new snow and ice control program. Today, the state uses a combination of different salts including liquid magnesium chloride to reach the desired objective. Rock salt is treated with the product or salt brine as it is dispensed from the plow trucks onto the roadway. According to DOT, this provides “an adhesive quality, which reduces its tendency to bounce and scatter off the pavement, making the application more effective. The liquid also activates the salt, which melts the snow into salt brine, which in turn melts more snow. Pre-wetting salt with this product helps it work much faster and more efficiently at colder temperatures. This results in improved pavement conditions faster than by using salt alone.” It does so in a manner that is less expensive and without clogging storm drains the way sand does, which creates hazardous runoff into our streams.

You may have also noticed what appears to be streaking white lines on the surface of bridges and certain stretches of roadway. These streaks are the result of salt brine pretreatment that is sprayed onto the pavement by a specially designed DOT truck up to five days in advance of a potential weather event. What you are seeing is a salt residue that becomes active when precipitation begins, thus helping to delay the surface from freezing and allowing DOT to get a jump on their storm operations.

As with any winter storm, the best way to keep our roads safe is for people to use extreme caution when driving. Hopefully the winter season is winding down, but if you are wondering why the roads might be a little more sparkle to them than they have been in the past, it’s probably because of environmentally friendly technologies.

If you have any questions about this subject or any other issue of concern, please email me at [email protected].