Alternatives and Best Practices

The following best practices were originally compiled in, Review of Effects and Costs of Road De-icing with Recommendations for Winter Road Management in the Adirondack Park, a comprehensive report underwritten and distributed by AdkAction. Prepared by Daniel L. Kelting, Executive Director, and Corey L. Laxson, Research Associate, at Paul Smith’s College Adirondack Watershed Institute.  

Map the road network: The New York State Department of Environmental Conservation (NYSDEC), working together with the Adirondack Park Agency (APA) and the Department of Transportation (NYSDOT) should utilize existing knowledge on the potentially harmful effects of road salt together with geospatial data to develop a map of sensitive areas. The state should then promulgate use of this map to tailor application rates, methods, and deicer types to minimize the environmental impacts of de-icing. Areas deemed too sensitive for any de-icing alternative should be marked with road signs to warn drivers of potentially icy conditions (like the warning signs already posted on many bridges).

Invest in RWIS: The State of New York should invest in a networked Road Weather Information System (RWIS). Being installed throughout the country now, these weather stations provide real time information on road and weather conditions. RWIS data allows the timing, the rate, and the type of de-icing chemical application to be tailored, which reduces application costs and increases deicer effectiveness. These systems can pay for themselves in one winter with the savings realized through decreased application costs.

Implement precision application: Precision application refers to the utilization of new technologies that ensure the de-icing or anti-icing chemicals are applied in the appropriate method and at the appropriate rate. Application rates are optimized through anti-icing practices, automatic vehicle location (AVL), vehicle-based sensor technologies, RWIS, and Management Decision Support Systems (MDSS).

Employ anti-icing: Anti-icing is the proactive use of any deicer with the intent of preventing snow and ice from bonding to the road surface. The advantages of anti-icing are that it: (1) maintains the roads at the best condition possible during winter storms, (2) uses fewer chemicals, therefore it is cost efficient and better for the environment, and (3) it makes subsequent road clearing easier. Anti-icing can decrease costs by greater than 50% compared to conventional de-icing (p57).

Use targeted application techniques: Conventional rotary spreaders throw a significant amount of deicer outside of the planned treated area (over 30 percent deicer waste has been reported); this wastes the deicer, reduces the effectiveness of the treatment and increases potential for off site impacts. More targeted methods reduce the amount of deicer needed and increase deicer effectiveness. Less deicer should be applied when rising temperature is forecasted while more deicer should be applied when decreasing temperature is forecasted.

Windrowing: Apply deicer in a concentrated 4 to 8ft wide strip down the centerline of lesser traveled roads, rather than to the entire surface. The snow melts faster and the exposed pavement warms and melts the adjacent untreated pavement.

Zero-velocity spreaders:  “Place” deicer on the road surface with little impact which minimizes bouncing and waste. By reducing the amount of waste, these spreaders can reduce materials cost by as much as 50 percent (p61).

Pre-wetting: The deicer becomes a melting agent when moisture is added, so pre-wetting can result in faster melting. Apply as brine using a spray delivery system, which also keeps the deicer on the surface being treated.

Use alternative deicers: In areas designated as too sensitive for road salt but also with high risk safety concern, use alternative deicers with fewer negative impacts. Trucks can have multiple bins and can switch de-icing types on the fly based on a map, or road signage that indicates the correct deicer to apply at a given location. Alternative deicers may also be warranted based on temperature. Road salt is most effective above 20°F, calcium chloride is effective down to 0°F, and magnesium chloride is effective down to -13°F. Thus, if sub 20°F temperatures are forecasted, deicers with lower effective temperatures should be used; else the road salt is wasted.

Upgrade equipment: Well maintained and calibrated automatic spreader systems have been shown to reduce unnecessary road salt application by over 40 percent (p61). Live-edge and double edge plows are more effective at removing snow and ice from road surfaces.

Improve training: A more sophisticated road de-icing plan requires greater operator training. Operators should be educated on the consequences of overuse of road salt, so they are aware of all the costs. Training modules for alternative deicers, application techniques, use of RWIS data, etc., are available from several sources. Training and annual follow-up continuing education should be mandated. Training modules need to be up-to-date.

Provide public education: The driving public should be informed about any new deicing practices and policies. The public has a vested interest in safe roads and a clean environment. Plus, public expectations dictate the level of service that must be provided, so an informed public can have more realistic expectations for driving during the winter months.

Implement, monitor, and evaluate: A comprehensive system should be put in place that facilitates implementation, tracks success and concerns, and allows for adaptive management. The NYS DOT should establish test areas along state routes in small watersheds to apply alternatives and monitor effectiveness and environmental and infrastructure impacts.