Maine Road Salt Risk Assessment Project University of Maine Maine Department of Transportation

Project Goals Develop among stakeholders a common understanding of the public policy issues and the relationships of funding, current research, levels of service, and risks associated with the use of road salt. Inform the policy making process in Maine related to winter road maintenance practices. Maine Road Salt Risk Assessment Project  University of Maine  September 2009

GOOD NEWS Level of Service = High Public Safety = Improved (causal link unclear) Environment = Less Sand/Silt in Runoff Maine Road Salt Risk Assessment Project  University of Maine  September 2009

GOOD NEWS BAD NEWS Level of Service = High Public Safety = Improved (causal link unclear) Environment = Less Sand/Silt in Runoff BAD NEWS Level of Service = High Cost Public Safety = Corrosion (vehicle/infrastructure) Environment = Salt Effects Maine Road Salt Risk Assessment Project  University of Maine  September 2009 4

UMaine Project Research Team Per Garder, Professor of Civil Engineering T. Olaf Johnson, Graduate Research Assistant, Department of Civil Engineering Margaret McKee, Research Associate, Margaret Chase Smith Policy Center Charles Morris, Senior Research Associate, Margaret Chase Smith Policy Center Kenneth Nichols, Professor of Public Administration John Peckenham, Director, Maine Water Research Institute & Senior Research Scientist, Senator George J. Mitchell Center for Environmental and Watershed Research Jonathan Rubin, Professor of Resource Economics & Policy, School of Economics & Margaret Chase Smith Policy Center Adam Stern, Graduate Research Assistant, School of Economics Maine Road Salt Risk Assessment Project  University of Maine  September 2009

Project Advisory Committee AAA Federal Highway Administration Federal Motor Carrier Safety Administration Maine Auto Dealers Association Maine Chapter of American Public Works Association Maine Chiefs of Police Association Maine Custom Auto Association Maine Department of Environmental Protection Maine Department of Inland Fisheries and Wildlife Maine Department of Public Safety Maine Department of Transportation Maine Fire Chiefs Association Maine Motor Transport Association Maine Municipal Association Maine State Legislature Maine Town and City Management Association Maine Turnpike Authority U.S. Department of Transportation U.S. Geological Survey, Water Resources Discipline Maine Road Salt Risk Assessment Project  University of Maine  September 2009

Maine Roads 22,830 miles of public roads MaineDOT 4,164 mi. (18%) MTA 635 lane miles 488 towns/cities 3 reservations counties

Maine Winter 20-40 storms November to late April Salt preferred chemical since 1930s Readily available Effective Relatively low-cost Maine Road Salt Risk Assessment Project  University of Maine  September 2009

Snow Removal Practices De-icing Plow after 1-2 inches. Spread sand and salt mix Remove snow pack (salt) Clean up sand at end of season Disadvantages of Sand Build up & drainage problems on roads Siltation of waterways Air quality issues Benefit is temporary. No melting properties Skidding hazard on pavement High cost of storage, handling Maine Road Salt Risk Assessment Project  University of Maine  September 2009

Anti-Icing 1996 FHWA SHRP Anti-Icing Manual of Practice Pre-Wet Solids Pre-Treat Roads MaineDOT initiated in late 1990s (salt priority) Mostly salt Requires accurate forecasting, timing Bare pavement sooner after storms Maine Road Salt Risk Assessment Project  University of Maine  September 2009

Current Practices MaineDOT Anti-icing 95% Salt is still most effective choice above 15o Pre-wetting salt with brine, with Ice-B-Gone, & with blend Pre-treating small percentage of roads Municipal/County Practices vary widely Sand and Salt  Liquids De-Icing  Anti-Icing and Pre-Treating Maine Road Salt Risk Assessment Project  University of Maine  September 2009

Materials Salt (NaCl) Winter Sand (mixed with salt) Salt Brine (23% salt in water, for pre-wetting or pre-treating) Chlorides Calcium Chloride (CaCl2) Magnesium Chloride (MgCl2) Ice-B-Gone (MgCl2 blend with by-product of alcohol distillation process) Acetates Potassium Acetate (KA) Calcium Magnesium Acetate (CMA) Carbohydrate based solutions Corn, Beet, Grains

Salt Usage in Maine 2008-09 * ** *estimate based on survey data **based on national estimate (USGS) Maine Road Salt Risk Assessment Project  University of Maine  September 2009

Municipal Practices: Percent Using These Materials winter 2008-09 Source: survey data

Level of Service (MaineDOT) Priority 1 (26%) 6 daylight hours to bare pavement, plow cycle 1 to 1 ½ hours 40-45 mph Route length 10 centerline miles Priority 2 (36%) 8 daylight hours, plow cycle 1 ½ to 2 hours 35-40 mph Route length 12 centerline miles Priority 3 (38%) 24 hours, plow cycle 1 ½ to 2 hours 35 mph Route length 14 centerline miles Source: MaineDOT 15

Level of Service: Municipal Source: survey data Maine Road Salt Risk Assessment Project  University of Maine  September 2009

Municipal Total Winter Maintenance Expenditures per Mile 2008-09 Source:l survey data

Municipal Practices: Winter Maintenance Budgets Personnel Equipment Materials Source: survey data Maine Road Salt Risk Assessment Project  University of Maine  September 2009

Material Cost MaineDOT Source: MaineDOT

Material Cost MTA Source: Maine Turnpike Authority

Total Winter Maintenance Expenditures 2008-2009 * *estimate based on survey data

Factors in snow control policy Level of Service Temperature Speed of response Availability & amount of material Melting properties Cost Equipment, training Infrastructure & environmental impact Driver reaction to snow clearing Vehicle condition Maine Road Salt Risk Assessment Project  University of Maine  September 2009

Road Salt Effects On Environmental Quality Maine Road Salt Risk Assessment Project  University of Maine  September 2009

OUTLINE Water Cycle Fate of Road Salt Mass Balances Environmental Receptors Pathways Mass Balances Summary of Research Water Quality Ecosystems Trends Summary and Conclusions Maine Road Salt Risk Assessment Project  University of Maine  September 2009

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Road Salt - Environmental Receptors Maine Road Salt Risk Assessment Project  University of Maine  September 2009

Environmental Receptors Road Salt – Pathways to Environmental Receptors Maine Road Salt Risk Assessment Project  University of Maine  September 2009

Road Salt – Mass Balances Maine Road Salt Risk Assessment Project  University of Maine  September 2009

Ion Exchange NaCl + H2O Na+ + Cl- aqueous 2Na+ Ca2+ Na+ K+ Mg2+ H+ In soil Maine Road Salt Risk Assessment Project  University of Maine  September 2009

Road Salt and Water Quality Short Term Increased Na and Cl in surface waters Long Term Increased Na and Cl in ground waters Increased salinity of ponds Soil chemistry change through ion exchange -release of Ca and Mg then H (acidification) Soil “stores” salt and releases it over time Trends Increased Na and Cl in surface waters (0.2 to 2 mg/L/yr) Increases persist for months to decades Occurrence of high salt waters limited to near roads and storage areas Maine Road Salt Risk Assessment Project  University of Maine  September 2009

Road Salt and Ecosystem Quality Short Term Increased attraction of salt-loving species Foliar burning Loss of salt sensitive species (plant and animal) Long Term Decrease in surface water diversity Dominance by salt-tolerant invasive species (e.g. phragmites) Vernal pool decline Toxic thresholds exceeded for sensitive species Trends Loss of overall diversity Increases in invasive species (plants) Ecological footprint ~ 600 meters wide Maine Road Salt Risk Assessment Project  University of Maine  September 2009

Maine Road Salt Risk Assessment Project  University of Maine  September 2009

SUMMARY AND CONCLUSIONS Road Salt Affects Water Quality and Ecosystems (600 m) Seasonal Effects- Larger Magnitude, Shorter Duration Chronic Effects- Lower Magnitude, Longer Duration Reversibility Seasonal Effects are mostly reversible Chronic Effects- Require years to decades to change Maine Road Salt Risk Assessment Project  University of Maine  September 2009

SUMMARY AND CONCLUSIONS Trends Increase in Chloride in surface waters and ground water Cation exchange leads to nutrient depletion and acidification of soil and water Loss of biodiversity Increased prevalence of invasive species Maine Road Salt Risk Assessment Project  University of Maine  September 2009

Infrastructure Corrosion Bridges 2,279 bridges in Maine 649 “structurally deficient or functionally obsolete” 28% (2007) 386 MaineDOT Watch List (2008) Pathways of corrosion Corrosion of steel React with cement paste Physical impact on cement (atmospheric) Maine Road Salt Risk Assessment Project  University of Maine  September 2009

Infrastructure Corrosion Increase # of freeze/thaw cycles. All chlorides equally high in corrosion of rebar. MgCl2 and acetates highest impact on paste deterioration. All chlorides high impact on atmospheric corrosion, with CaCl2 and MgCl2 higher due to retention of moisture. NCHRP Study 577 (2008) Maine Road Salt Risk Assessment Project  University of Maine  September 2009

Vehicle Corrosion Trucking Industry: “rust jacking” Automobiles: brake lines & electrical connectors Photo courtesy of Jeremy Williams Maine Road Salt Risk Assessment Project  University of Maine  September 2009

Vehicle Corrosion Issues: Multiple types of corrosion Variety of metals and alloys in vehicles Environmental factors Chemical factors Field tests vs. laboratory tests Maine Road Salt Risk Assessment Project  University of Maine  September 2009

Hexavalent Chromium Alternatives? End-of-Life Vehicle Directive, July 2007 deadline Eliminated: 1990s Volvo, Opel 2003-2006 GM 2004-06 VW 2005 Ford 2006 Toyota, Hyundai 2007 Nissan, DaimlerChrysler Alternatives? Maine Road Salt Risk Assessment Project  University of Maine  September 2009

Conclusions Chloride-based salts are all corrosive to motor vehicle components in laboratory tests. Magnesium and calcium chlorides retain moisture longer. Inconsistency of laboratory results means no risk ranking of chemicals possible. (Fay, 2009) Diffusion of chloride into porous materials is linked to moisture. Field conditions may contribute more to relative corrosiveness than chemical or coating. (NCHRP, 2008) Maine Road Salt Risk Assessment Project  University of Maine  September 2009

Road Salt Safety Maine Road Salt Risk Assessment Project  University of Maine  September 2009

Data All police reported accidents in Maine from 1989-2008. Annual estimated vehicle miles traveled (VMT) for all individual counties in Maine as well as state totals. Maine Road Salt Risk Assessment Project  University of Maine  September 2009

Crashes by Road Surface Condition 1989-2008 Maine Road Salt Risk Assessment Project  University of Maine  September 2009

County Crash Rates 1989-2008 Maine Road Salt Risk Assessment Project  University of Maine  September 2009

Total Crashes 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 January February March April May June July August September October November December 2002 2004 2006 2008 Maine Road Salt Risk Assessment Project  University of Maine  September 2009

Fatality Rates Compared Winter conditions Dry Pavement Maine Road Salt Risk Assessment Project  University of Maine  September 2009

Maine & US Crash Rates 1989-2008 Maine Road Salt Risk Assessment Project  University of Maine  September 2009

Costs of Accidents Maine accident data shows a 10 year average cost of $1.5 billion dollars annually Cost per accident measured in constant $2008 The total number of accidents has fallen 26% over the decade. Possible reasons: driver behavior, vehicle technology, road way improvements, winter maintenance. Maine Road Salt Risk Assessment Project  University of Maine  September 2009

Thank you University of Maine Road Salt Risk Assessment Team http://mcspolicycenter.umaine.edu/?q=RoadSalt Maine Department of Transportation