Response to ‘Sand versus salt — difficult decisions’
In Oct. 27’s “Sand versus salt” article, author Dave Werner does a fine job outlining the many variables that a highway department must take into account when determining the best treatment for a particular road in the winter. He then weighs the pros and cons of using sand to treat road surfaces in the winter, but doesn’t go into detail on the advantages and disadvantages associated with using salt. I will do that here and explain why “sand or salt” oversimplifies the situation.
Pros: Road salt, sodium chloride, is relatively cheap (when you look at material cost alone), widely available, and highly effective at melting snow and ice above 15 degrees F. Notably, most plow trucks on the road today are designed to store and spread solid materials such as salt or sand.
Cons: Sodium chloride is highly corrosive and costs taxpayers millions of dollars in equipment and infrastructure repair and replacement. Data compiled in 2020 for an economic analysis of road salt impact found that, at average road salt distribution levels, winter road care costs municipal governments an estimated $25,000 per road mile. The cost to maintain, repair and replace salt-corroded infrastructure accounts for 74% of this estimate, which also factors in vehicle damage and depreciation, public health and environmental costs, and the up-front cost of salt itself. Road salt is practically ineffective below 15 degrees Fahrenheit, and as much as a third of the salt that is applied to roadways bounces and scatters from the road surface, where it finds its way into adjacent soils and water. It can leach heavy metals from roadside soils and from plumbing, and is capable of mobilizing lead that can get into drinking water in homes with private wells. Heavy metals aside, salt-contaminated drinking water is not just a costly nuisance — for people with high blood pressure and other health conditions, it creates a serious public health hazard.
The difficult decision is no longer simply “sand or salt.”
The majority of municipalities in the Adirondacks use sand with just enough salt mixed in to prevent the pile from freezing in clumps. For most highway departments we have talked to, sand is working well, and crews are well-versed in minimizing environmental impacts by optimizing application techniques and sweeping up excess sand each spring to prevent sediment runoff into adjacent waters. Even so, there are some conditions that call for chemical de-icing, such as the use of road salt.
Despite all of the cons associated with road salt, it is still a powerful tool for winter road maintenance. Abolishing road salt completely is out of the question, barring significant advancements in technology. The key, then, is to do everything in our power to avoid applying more road salt than is necessary to achieve and maintain safe driving conditions.
Winter road maintenance is becoming increasingly complex, with sand and salt being two tools in the toolbox of a well-trained highway maintenance professional. There is no silver bullet or perfect alternative to road salt; rather, a nuanced approach is needed.
Some of these alternatives and best practices that highway departments and the New York State Department of Transportation are now using and considering include:
¯ Optimizing application rates by using technologies like automatic vehicle location, vehicle-based sensors, management decision support systems and networked Real Weather Information Systems. These technologies allow for the timing, rate and type of de-icing application to be tailored, increasing effectiveness and decreasing cost.
¯ Calibrating equipment. Keeping automatic spreader systems calibrated and well-maintained further reduces road salt waste.
¯ Employing anti-icing (applying liquid de-icer preventatively), which maintains the best possible conditions while using fewer chemicals and has been shown to decrease costs by 50% compared to conventional de-icing (using chlorides during or after a storm).
¯ Using targeted application techniques. Conventional rotary spreaders throw a significant amount of de-icer outside of the planned treated area. Targeted methods include zero-velocity spreaders that “place” de-icer on the road with little impact, which reduces bouncing and waste.
¯ Using windrows. Applying de-icer in a concentrated 4- to 8-foot-wide strip down the centerline of lesser traveled roads, rather than to the entire surface. The exposed pavement quickly warms and melts adjacent, untreated pavement.
¯ Using alternative de-icers in designated areas that are too sensitive for road salt but with high-risk safety concerns. Trucks with multiple bins can switch de-icing types on the fly based on a map, temperature, forecast, or road signage that indicates the correct de-icer to apply at a given location.
¯ Upgrading equipment, including the use of live-edge and double-edge plows, which are more effective at removing snow and ice from road surfaces.
¯ Selectively clearing the canopy. Cutting back some evergreen tree species along roadsides will allow the sunlight to pass through the leafless hardwood species and melt snow and ice on roadways during the day.
¯ Investing in training. A more sophisticated road de-icing plan requires greater operator training and ongoing continuing education to keep operators up-to-date.
¯ Educating the driving public. The driving public is a key partner that should be engaged and educated about any new de-icing practices and policies so they have a full understanding and realistic expectations for driving during the winter months.
AdkAction and the rest of the Adirondack Road Salt Working Group are working to foster a unified regional strategy to reduce road salt pollution and to publicly recommend and support alternative de-icing products, techniques and best management practices like those listed above.
Many of the recommendations in this article were originally compiled in a comprehensive report, “Review of Effects and Costs of Road de-icing with Recommendations for Winter Road Management in the Adirondack Park,” prepared by Daniel L. Kelting, executive director, and Corey L. Laxson, research associate, at the Paul Smith’s College Adirondack Watershed Institute. Data for the economic impact of road salt were compiled by Colgate University Road Salt Fellow Kelsey Bennett in June 2020.
Brittany Christenson is executive director of AdkAction, based in Saranac Lake.