Review of Effects and Costs of Road De-icing with Recommendations for Winter Road Management in the Adirondack Park
Adirondack Watershed Institute
Daniel Kelting & Corey Laxson
This document provides a comprehensive evaluation of road salt and recommendations for managing snow and ice on winter roads to minimize environmental impacts and increase management effectiveness. It argues that the use of best management practices can reduce the negative impacts of road salt on the environment, while simultaneously improving road safety and saving money.
Sodium chloride (road salt) is used throughout the winter months in the Adirondacks to maintain clear roads. Road salt can be an effective and economical choice for de-icing when applied correctly as part of a comprehensive highway de-icing management system; however, numerous studies have documented the negative effects of road salt on forest and aquatic ecosystems, drinking water, vehicles, and infrastructure. When considering these negative effects, the effectiveness and economical arguments for road salt are called into question, as these often hidden, chronic, and cumulative costs may outweigh the short term benefits.
The environmental cost of road salt was estimated by valuing the ecosystem services impacted by road salt using $ per acre per year estimates from the scientific literature. A simulation of road salt impacts on surface waters and forests showed a $2,320 per lane mile per year reduction in environmental value that easily offset the estimated $924 per lane mile per year spent on road salt. This large hidden cost of road salt shows that other “more expensive” deicers are actually lower cost options than road salt. The high environmental cost of road salt shows that more funds should be invested in advanced technology and alternative deicers to improve the environmental performance of winter road management.
Completely replacing road salt with alternative deicers (e.g. calcium chloride or calcium magnesium acetate, CMA) is not a realistic option given budgetary constraints, and these alternatives are not without concerns (e.g. chloride is chloride). All deicers rapidly lose their effectiveness (tons melted per ton deicer applied) as pavement temperature decreases. Road salt is marginally effective below 15oF, requiring very high application rates at low temperatures, and most state DOTs do not recommend applying road salt below this temperature. However, Mg and Ca chloride salts are still effective at low temperatures, requiring 1/3 the amount of road salt to melt the same amount of snow and ice. These chlorides are also less harmful to the environment, actually having beneficial effects on road side soils, versus road salt that can degrade road side soils.