Cover
Title Page
List of Contributors
Foreword
1 Introduction to Sustainable Winter Road Maintenance
1. 1.1 Introduction
2. 1.2 How the Chapters and Topics Are Organized
3. References
2 A Framework for Life‐Cycle Sustainability Assessment of Road Salt Used in Winter Maintenance Operations
1. 2.1 Introduction
2. 2.2 Concepts of LCSA
3. 2.3 Complexities and Caveats in the LCSA of Road Salt
4. 2.4 A Preliminary LCSA Framework of Road Salt
5. 2.5 Conclusions
6. Acknowledgements
7. Questions
8. References
3 Winter Road Operations
1. 3.1 Overview
2. 3.2 Pre‐Strategic Highway Research Program (Prior to 1987)
3. 3.3 The Strategic Highway Research Program (1987–1991)
4. 3.4 Post Strategic Highway Research Program (After 1991)
5. 3.5 Other Major Efforts Contributing to “Sustainable Winter Road Maintenance Operations”
6. References
4 Societal and User Considerations for Sustainable Winter Road Operations
1. 4.1 Introduction
2. 4.2 Societal/User Expectations Related to Winter Maintenance Operations
3. 4.3 Traveler Decision‐Making
4. 4.4 Agency Performance Measures in Use
5. 4.5 Summary
6. Questions and Answers
7. References
5 Weather Services for Sustainable Winter Road Operations
1. 5.1 Introduction
2. 5.2 Road Weather Basics
3. 5.3 The Meteorology of Road Weather
4. 5.4 Road Weather Forecasting Operations
5. 5.5 Road Weather Information Systems (RWIS)
6. 5.6 Concluding Remarks
7. List of Acronyms
8. References
9. Recommended Further Reading
6 The Fundamentals of Plowing, Anti‐icing, De‐icing and Sanding
1. 6.1 Introduction
2. 6.2 Fundamentals of Plowing
3. 6.3 Fundamentals of Anti‐ and De‐icing Chemicals in Winter Maintenance
4. 6.4 Fundamentals of Sanding
5. Acknowledgments
6. References
7 Safety Effects of Winter Weather and Road Maintenance Operations
1. 7.1 Introduction
2. 7.2 Factors Affecting Winter Road Safety
3. 7.3 Winter Road Safety Management
4. 7.4 Methods for Quantifying the Safety Benefits of Winter Road Maintenance
5. 7.5 Case Studies
6. 7.6 Conclusions
7. Review Questions
8. Appendix: Development of Winter Collision Prediction Models
9. Statistical Models for Injury Severity
10. Model Assessment and Testing
11. References
8 Mobility Effects of Winter Weather and Road Maintenance Operations
1. 8.1 Introduction
2. 8.2 Factors Affecting Winter Mobility and Traffic
3. 8.3 Effects of Adverse Winter Weather on Macroscopic Traffic Parameters
4. 8.4 Effects of Adverse Winter Weather on Microscopic Traffic Parameters
5. 8.5 Methods for Quantifying the Mobility Benefit of Winter Road Maintenance
6. 8.6 Mobility Benefits of Winter Road Maintenance – An Example
7. 8.7 Conclusions
8. Review Questions
9. References
9 Economic Benefits of Winter Road Operations
1. 9.1 Overview
2. 9.2 Defining Winter Maintenance Benefits
3. 9.3 Methods to Estimate Winter Maintenance Benefits
4. 9.4 Benefits of Winter Maintenance
5. 9.5 Benefit‐Cost Analysis in Winter Maintenance
6. 9.6 The Benefit‐Cost Approach
7. 9.7 Benefit‐Cost Analysis Example
8. 9.8 Available Analysis Tools and Guides
9. 9.9 Summary
10. Questions and Answers
11. References
10 Environmental Risks of Snow and Ice Control Materials
1. 10.1 Introduction
2. 10.2 Factors That Define the Environmental Impacts of Materials
3. 10.3 Environmental Assessment of Snow and Ice Control Products
4. 10.4 Concluding Remarks
5. Questions and Answers
6. References
11 Impact of Chemical Deicers on Roadway Infrastructure: Risks and Best Management Practices
1. 11.1 Introduction
2. 11.2 Deicer Effects on Hydraulic Cement Concrete
3. 11.3 Deicer Effects on Asphalt Concrete
4. 11.4 Deicer Effects on Embedded Steel Rebar or Dowel Bar
5. 11.5. Effects of Winter Road Operations on Other Infrastructures
6. 11.6 Concluding Remarks
7. Review Questions
8. References
12 Vehicle Risks of Winter Road Operations and Best Management Practices
1. 12.1 Introduction
2. 12.2 Corrosion Definition
3. 12.3 Causes and Effects of Corrosion
4. 12.4 New Equipment Specification
5. 12.5 Preventive Maintenance Practices for Equipment
6. 12.6 Laboratory Test Methods for Anti‐corrosion Practices
7. 12.7 Conclusions
8. References
13 Strategic Planning and Management for Sustainable Winter Road Maintenance
1. 13.1 Introduction
2. 13.2 Network Partitioning or Districting
3. 13.3 Fleet Sizing
4. 13.4 Routing
5. 13.5 Crew Scheduling
6. 13.6 RWIS: Region‐wide Implementation Guidelines and Methods
7. 13.7 Salt Management Plans (SMPs)
8. 13.8 Concluding Remarks
9. Review Questions
10. References
14 Source Control Tactics for Sustainable Winter Road Maintenance
1. 14.1 Introduction
2. 14.2 Innovative Snow Fences for Drift Control
3. 14.3 Anti‐icing, Deicing, and Pre‐wetting Practices
4. 14.4 Maintenance Decision Support Systems (MDSS)
5. 14.5 Fixed Automated Spray Technology (FAST)
6. 14.6 Equipment Maintenance and Calibration
7. 14.7 Advanced Snowplows and Spreaders
8. 14.8 Material and Snow Storage
9. Review Questions
10. References
15 Reactive Approaches for Environmentally Sustainable Winter Road Operations
1. 15.1 Introduction
2. 15.2 Use of Structural BMPs to Manage Suspended Solids
3. 15.3 Use of Traditional Structural BMPs to Manage Chlorides
4. 15.4 Criteria for Selecting Structural BMPs
5. 15.5 Alternative Methods to Remove Chlorides
6. 15.6 Cleanup and Recycling of Winter Maintenance Abrasives
7. 15.7 Recycling of Salt Brine
8. 15.8 Conclusions
9. References
10. Further Reading
16 Innovative Winter Maintenance Equipment
1. 16.1 Introduction
2. 16.2 Determining the Need for Innovative Equipment
3. 16.3 Areas of Innovative Equipment
4. 16.4 Quantifying the Benefits of Innovation
5. 16.5 Decision Matrix for a Case Study
6. 16.6 Conclusion
7. Acknowledgement
8. References
17 The Search for “Greener” Materials for Winter Road Maintenance Operations
1. 17.1 Introduction
2. 17.2 Holistic Approach to Materials Evaluation and Selection
3. 17.3 Recent Advances in Alternative Deicers and Additives
4. 17.4 A Case Study of Developing “Green” Liquid Deicers
5. 17.5 Concluding Remarks
6. References
18 Pavement Treatments for Sustainable Winter Road Maintenance
1. 18.1 Introduction
2. 18.2 Physical Modification of Pavement Surface
3. 18.3 High‐friction Anti‐icing Polymer Overlays
4. 18.4 Asphalt Pavement With Anti‐icing Additives
5. 18.5 Heated Pavement Technologies
6. 18.6 Other Advanced Technologies
7. 18.7 Concluding Remarks
8. Review Questions
9. References
19 Performance Measures for Sustainable Winter Road Operations
1. 19.1 Introduction
2. 19.2 Overview of Performance Evaluation Components
3. 19.3 Considerations for Selecting Inputs, Outputs, Outcomes, and Normalization Factors
4. 19.4 Putting It All Together — How to Use Inputs, Outputs, Outcomes, and Normalization Factors in an Example
5. 19.5 Presenting the Data
6. 19.6 Review of Key Points
7. 19.7 Putting It All Together — How to Use Inputs, Outputs, Outcomes, and Normalization Factors in an Example
8. 19.8 Presenting the Data
9. Review Questions
10. References
20 Application Guidelines for Optimal Deicing and Anti‐icing
1. 20.1 Introduction
2. 20.2 Current Practices for Snow and Ice Controls
3. 20.3 Optimal Deicing and Anti‐icing – Factors to Consider
4. 20.4 Snow‐melting and Application Rates Models
5. Questions
6. References
21 A Look into the Future
1. 21.1 Introduction
2. 21.2 Main Challenges in WRM
3. 21.3 New Opportunities
4. 21.4 Future Research and Development
5. References
Index
End User License Agreement

List of Tables

Chapter 06
1. Table 6.1 Description of highway moisture. (Raukola, 1993. Reproduced with permission of Transportation Research.
Chapter 07
1. Table 7.1 Effects of weather‐related factors on collision frequency.
2. Table 7.2 Effects of weather‐related factors on collision severity.
3. Table 7.3 Data used for case studies.
4. Table 7.4 Benefit calculation for Target RSI.
Chapter 08
1. Table 8.1 Pavement conditions and associated speed reduction factors. (Ye, 2013. Reproduced with permission of National Research Council).
2. Table 8.2 Traffic volume distribution over the event.
3. Table 8.3 Traffic volume distribution over the event.
4. Table 8.4 Travel Time Savings for Scenarios A (with WRM) and B (without WRM).
Chapter 09
1. Table 9.1 RWIS benefit and cost inputs.
2. Table 9.2 Laser Guide benefit and cost inputs, results.
Chapter 10
1. Table 10.1 Colorado DOT‐ and PNS‐defined heavy metals of interest and their total allowable limits in deicer products. (Fay and Shi 2012. Reproduced with permission of Springer).
2. Table 10.2 A summary of test methods for deicer toxicity.
3. Table 10.3 Summary of environmental impacts of abrasives.
4. Table 10.4 Summary of the measured chloride concentrations from various aquatic environments.
5. Table 10.5 Summary of the environmental impacts of chloride deicers.
6. Table 10.6 Summary of the environmental impacts of acetate‐ and formate‐based deicers.
7. Table 10.7 Summary of the environmental impacts of glycols and urea.
8. Table 10.8 Summary of the environmental impacts of agro‐based deicers.
Chapter 11
1. Table 11.1 Eutectic and effective temperature comparison.
2. Table 11.2 Cost of concrete bridge corrosion.
Chapter 12
1. Table 12.1 Estimated risk of equipment corrosion due to deicer exposure alone and annual costs of estimated equipment corrosion risks due to deicer exposure (Shi et al., 2013).
Chapter 13
1. Table 13.1 Ratios and distances for each cycle shown in Figure 13.1.
2. Table 13.2 Ontario Ministry of Transportation Maintenance Standards. (Government of Ontario 2013, Ontario Ministry of Transportation 2016).
3. Table 13.3 Event category, City of Toronto.
4. Table 13.4 RWIS‐enabled winter maintenance practices and associated benefits. (Reproduced from Boon and Cluett 2002).
5. Table 13.5 Traffic and weather attributes for each cell.
6. Table 13.6 Salt management plan, sample goals. Derived from the City of Toronto’s Salt Management Plan, 2004.
7. Table 13.7 Sample level of service policy. Derived from the City of Toronto’s Salt Management Plan, 2004.
8. Table 13.8 Sample deicing level of service policy. Derived from the City of Toronto’s Salt Management Plan.
Chapter 15
1. Table 15.1 Summary of influent and effluent statistics for total suspended solids (mg/L). (Adapted from Clary, J., Jones, J., Leisenring, M., and Strecker, E., 2017. International Stormwater BMP Database 2016 Summary Statistics. WE&RF: Alexandria, VA. EMCs denote Event Mean Concentrations).
2. Table 15.2 Summary of selection criteria for structural BMPs.
3. Table 15.3 A BMP selection tool by the Oregon Department of Transportation. (ODOT 2008).
4. Table 15.4 Risk, compliance issues, and management examples for highway‐generated wastes. (adapted from Leisenring et al. 2014).
5. Table 15.5 Summary of reactive mitigation measures.
Chapter 16
1. Table 16.1 Decision matrix example for tow‐behind plow utilization scenarios.
Chapter 17
1. Table 17.1 Normalized assessment of deicers and sand by the selected 18 parameters.
2. Table 17.2 Normalized assessment of deicers and sand by the select four dimensions and the composite indices calculated from them.
Chapter 18
1. Table 18.1 Cost estimates for various heating systems for snow and ice control. (Zhang et al. 2009).
2. Table 18.2 Pavement heating system costs per season, in 1972 USD. (Murray and Eigerman 1972).
3. Table 18.3 Cost data of a geothermal heating system in Virginia, in 2000 USD. (Hoppe 2000).
4. Table 18.4 Materials costs of conductive concrete versus conventional concrete, in 1998 USD. (Yehia and Tuan 1999).
5. Table 18.5 Comparison of different deicing systems. (Tuan 2008).
Chapter 19
1. Table 19.1 Available information from the 10 depots.
2. Table 19.2 Calculating the Weather Normalization Factor.
3. Table 19.3 Calculating the Mile Normalization Factor.
4. Table 19.4 Reconfiguring the table to include Inputs, Outputs, Outcomes, and Normalization Factors.
5. Table 19.5 Computation of “Normalized Cost”.
Chapter 20
1. Table 20.1 Snow control strategies and methods and LOS expectations. (Blackburn 2004. reproduced with permission of Transportation Research Board).
2. Table 20.2 Model to estimate pavement surface temperature from weather variables.
3. Table 20.3 Description of pavement snow and ice condition. Reproduced from NCHRP‐525.
4. Table 20.4 Recommended application rates for salts. (Blackburn 2004. Reproduced with permission of Transportation Research Board).
5. Table 20.5 Dilution rates. (Blackburn 2004. Reproduced with permission of Transportation Research Board).
6. Table 20.6 Application rate conversion factors for different salt types. (Blackburn 2004. Reproduced with permission of Transportation Research Board).
7. Table 20.7 Application rate. (Reproduced with permission of Raukola 2001).
8. Table 20.8 Application rates for pedestrian and parking lot facilities.

List of Illustrations

Chapter 01
1. Figure 1.1 U.S. areas affected by snow and ice
2. Figure 1.2 Key components and processes in winter transportation operations
3. Figure 1.3 WRM operations are vital to economy and society.
4. Figure 1.4 Relationship between individual book chapters.
Chapter 02
1. Figure 2.1 Harvey’s LCC procedure (Harvey, 1976).
2. Figure 2.2 The LCA framework based on the ISO 14040 standard.
3. Figure 2.3 Five simplified stakeholder categories in the production system.
4. Figure 2.4 The interactions between LCC, LCA, SLCA and LCSA.
5. Figure 2.5 The interactions considered in the LCSA of road salt.
6. Figure 2.6 The LCSA fishbone diagram of road salt used in WRM operations.
Chapter 03
1. Figure 3.1 Phase I illustration of highway maintenance concept vehicle.
2. Figure 3.2 Phase II highway maintenance concept vehicle.
3. Figure 3.3 Phase IV highway maintenance concept vehicle.
4. Figure 3.4 European snow plows with snow plow shields.
5. Figure 3.5 Snow plow truck plowing with snow plow shield.
6. Figure 3.6 Rear‐mounted air deflector (truck on right) and snow‐covered tail gate and lights (truck on left) without air deflector.
Chapter 04
1. Figure 4.1 Example of an LOS D condition, moderate pavement snow cover.
Chapter 05
1. Figure 5.1 Cross‐section of road and atmosphere representing the approximate size of the near‐surface atmosphere, within which we assume conditions are relatively the same.
2. Figure 5.2 For the United States East Coast Blizzard of 22–24 January 2016: (a) Surface analysis including surface observations, surface wind speed and direction (wind barbs), pressure isobars (lines), low‐pressure center (“L”), cold front (triangles), and warm front (semicircles) at 23 January 0300 GMT; and (b) visible satellite image of the cyclone at 23 January 0312 GMT.
3. Figure 5.3 Graphical representation of forecast time scales.
4. Figure 5.4 Screenshots of pavement condition and temperature forecasts for a fictional roadway.
5. Figure 5.5 METRo model output examples showing (a) map view of natural (not accounting for mitigation efforts) road snow accumulation expected from a storm in France and (b) graphical view of model output parameters related to atmospheric, road surface and subsurface conditions. Both outputs shown here have been combined with other forecasting models in order to produce the desired result.
6. Figure 5.6 Screenshot of Iteris’s MDSS (version 13.00) graphical user interface in map view.
7. Figure 5.7 Diagram showing an RWIS‐ESS and representative instrumentation.
Chapter 06
1. Figure 6.1 Factors affecting the pavement surface conditions.
2. Figure 6.2 The main elements of a snow plow.
3. Figure 6.3 The effect of plowing speed on the snow clearance performance.
4. Figure 6.4 Retractable rubber elements mounted behind the cutter edge for improved slush removal.
5. Figure 6.5 Phase diagram of sodium chloride in water.
6. Figure 6.6 Measurement of the amount of water on the pavement.
7. Figure 6.7 Illustration of the freezing process of saline water on a molecular level. As freezing progresses, salt is expelled and concentrated in the remaining liquid. This decreases the freezing point.
8. Figure 6.8 Illustration of the bond process between snow crystals.
9. Figure 6.9 Illustration of the equilibrium between ice and water.
10. Figure 6.10 Melting ice with salt. The salt lowers the freezing point and prevents the molecules freezing, while the melting still continues.
11. Figure 6.11 The calculated melting capacity of solid NaCl and NaCl brine.
12. Figure 6.12 Illustration of the adhesion mechanism at molecular level with bonds being formed, stretched until breakage and reformed.
13. Figure 6.13 Rubber‐pavement interlocking occurs on different levels of magnification.
14. Figure 6.14 Top view of a compacted snow layer, after compaction by traffic. The material is very porous, providing significant surface roughness.
15. Figure 6.15 Sand particles embedded in an ice layer after passage of a braking aircraft tire. All sand particles visible in the track are firmly frozen/embedded into the ice.
16. Figure 6.16 A sanded, iced runway showing scratch marks (thin white stripes running vertically in the picture). These scratch marks were caused by sand particles entrapped by braking aircraft tires.
Chapter 07
1. Figure 7.1 Factors influencing highway performance under winter conditions.
2. Figure 7.2 Roadway safety management process.
3. Figure 7.3 Road Surface Classes and Road Surface Index.
4. Figure 7.4 Road surface conditions and definition of snowstorm event.
5. Figure 7.5 RSI profile for different BPRTs.
6. Figure 7.6 Road Surface Conditions vs. Maintenance Timing.
7. Figure 7.7 Safety benefit vs. maintenance timing.
8. Figure 7.8 Additional safety benefit for achieving a given LOS target.
Chapter 08
1. Figure 8.1 Interactions between multiple factors and their influences on mobility.
2. Figure 8.2 Traffic stream models (FFS and Capacity) and effect of road weather conditions.
3. Figure 8.3 Schematic of WRM benefit calculation for a single weather event using macroscopic analysis.
4. Figure 8.4 Schematic of WRM benefit calculation for a single weather event using microscopic simulation analysis.
5. Figure 8.5 Simulated traffic network using INTEGRATION and loop‐detector locations.
6. Figure 8.6 Calibration results for (a) speed and (b) capacity.
7. Figure 8.7 Mobility benefits of achieving bare pavement as a percentage of travel time of snow‐covered scenario.
8. Figure 8.8 A graphical illustration of the event and two WRM scenarios considered.
9. Figure 8.9 A graphical illustration of the two scenarios considered.
10. Figure 8.10 Mobility benefit vs. maintenance timing.
11. Figure 8.11 Mobility benefit of WRM vs. WRM LOS standard for Ontario Provincial Network.
Chapter 09
1. Figure 9.1 Costs and benefits associated with winter maintenance.
Chapter 10
1. Figure 10.1 Atmospheric and pavement condition parameters to be considered to determine the appropriate application rate of deicers.
2. Figure 10.2 Schematic of deicer migration off the roadway into various environments where it can exert impacts.
3. Figure 10.3 Pathways of snow and ice control material transport in the environment.
4. Figure 10.4 Sodium and chloride aquatic toxicity for selected fish species.
5. Figure 10.5 Typical symptoms of road plants with different degrees of injury caused by deicing salt pollution.
Chapter 11
1. Figure 11.1 Damage pattern of salt scaling on concrete surface.
2. Figure 11.2 Thickness distribution of scaled‐off materials.
3. Figure 11.3 Results indicated that maximum damage occurs at a solute concentration of ~3%, and that this trend is independent of solute type.
4. Figure 11.4 Weight loss of cement concrete specimens following SHRP H205.8 test in various solutions (Shi et al., 2009b).
5. Figure 11.5 Smart pebbles concept (Watters et al., 2003).
6. Figure 11.6 Corrosion of a steel cable barrier (photo taken by Xianming Shi).
Chapter 12
1. Figure 12.1 Pitting corrosion diagram on stainless steel.
2. Figure 12.2 General corrosion.
3. Figure 12.3 Pitting corrosion.
4. Figure 12.4 Crevice corrosion.
5. Figure 12.5 Galvanic corrosion.
6. Figure 12.6 Filiform corrosion.
7. Figure 12.7 Intergranular corrosion.
8. Figure 12.8 Stress corrosion cracking.
9. Figure 12.9 Corrosion fatigue.
10. Figure 12.10 Erosion corrosion in a pipeline with a T‐shape geometry (a), corroded metallic cap (b), and pitted zone (c) (Hernández‐Rodríguez et al., 2016; with permission from Elsevier).
11. Figure 12.11 Fretting corrosion.
12. Figure 12.12 Microbiologically influenced corrosion.
13. Figure 12.13 Allocation of corrosion‐related repair costs among WSDOT equipment (Shi et al., 2013).
14. Figure 12.14 Images of corrosion damage on winter maintenance vehicles.
15. Figure 12.15 Temporal evolution of polarization resistance of carbon steel coupons (C1010, A), stainless steel coupons (SS304L, B) and aluminum alloy coupons (Al1100) in 30 wt.% MgCl₂ solution.
16. Figure 12.16 Digital photos of pressure‐washed samples exposed to 10% MgCl₂ containing 5% sugar beet by‐product (a) and 10% MgCl₂ (b) after a six‐day dip‐dry test.
Chapter 13
1. Figure 13.1 Sample partitioning of a small network into elementary cycles.
2. Figure 13.2 Major components of an RWIS station (Reproduced from Kwon et al. 2014).
3. Figure 13.3 (a) VST, (b) SWE, (c) WAR, and (d) HT.
4. Figure 13.4 Proposed RWIS station locations – Ontario, Canada.
5. Figure 13.5 Implementation of the CB‐based method.
6. Figure 13.6 Implementation of the CB‐based method.
7. Figure 13.7 Implementation of the CB‐based method.
8. Figure 13.8 A comparison of RWIS density charts – per unit area (10,000 km²).
9. Figure 13.9 A linear relationship of correlation range vs. area (km²).
10. Figure 13.10 A simple network with ten potential RWIS station locations.
11. Figure 13.11 The three selected RWIS sites using the SI‐based approach.
12. Figure 13.12 Main components of salt management plan.
13. Figure 13.13 (Top) A change in gradient can cause snow to accumulate, possibly blocking a roadway. (Bottom) Obstructions such as trees, fencerows, or buildings can also cause snow to accumulate, possibly blocking a roadway.
Chapter 14
1. Figure 14.1 The fetch concept used to estimate snow transport.
2. Figure 14.2 Schematic design of an LSF (Wyatt et al., 2012).
3. Figure 14.3 Details of typical landscape layout of an LSF.
4. Figure 14.4 An example ground profile required to generate the snowdrift profile in the region of interest.
Chapter 15
1. Figure 15.1 Process showing the combined use of various BMPs to provide flow control, courtesy of E. Strecker. TSCs denote Temporary Sediment Controls.
Chapter 16
1. Figure 16.1 Advantages and disadvantages of traditional and innovative equipment. (Note that Figure 16.1 contains general statements and all may not apply in their entirety to all traditional and innovative equipment.)
2. Figure 16.2 Feasibility of innovative equipment.
3. Figure 16.3 Areas of innovative equipment.
4. Figure 16.4 Road treating equipment components.
5. Figure 16.5 Hopper with increased spreading capacity for chemical treatment.
6. Figure 16.6 Tanker for liquid treatment.
7. Figure 16.7 Trucks with higher plowing capacity.
8. Figure 16.8 Monitoring equipment options.
9. Figure 16.9 Examples of asset management and its purpose.
10. Figure 16.10 Costs associated with winter maintenance.
11. Figure 16.11 Data fusion for innovative equipment evaluation.
12. Figure 16.12 Example of data fusion.
13. Figure 16.13 Determining ideal areas for implementation of a tow‐behind plow.
Chapter 17
1. Figure 17.1 Process for developing “green” deicers.
2. Figure 17.2 DSC thermograms for 23% NaCl solution, Mix 3, and Mix 22.
3. Figure 17.3 Ice‐melting performance after 60 min at −1.1 °C (30 °F). Error bars were calculated from triplicates.
4. Figure 17.4 Ice‐melting performance after 60 min at −9.4 °C (15 °F). Error bars were calculated from triplicates.
5. Figure 17.5 Ice‐melting performance at −6.7 °C (20 °F), 60 min.
6. Figure 17.6 Temporal evolution of ice melt of various liquid deicers at −6.7 °C (20 °F).
7. Figure 17.7 Results of the NACE TM0169–95 PNS Modified Dip Test.
8. Figure 17.8 Weight loss results of half‐air‐entrained mortar specimens following the SHRP H205.8 freeze–thaw test.
9. Figure 17.9 STS and weight loss following the SHRP H205.8 freeze/thaw test.
Chapter 18
1. Figure 18.1 Photos of the first snow‐melting observation. (a) Asphalt mixture containing MF; (b) Asphalt mixture containing Mg₂/Al‐Ac⁻ LDH; (c) Asphalt mixture containing Cl⁻DIA; (d) Asphalt mixture containing MF after 4 hrs; (e) Asphalt mixture containing Mg₂/Al‐Ac⁻ LDH after 4 hrs; (f) Asphalt mixture containing Cl⁻DIA after 4 hrs (Peng et al. 2015).
2. Figure 18.2 Photos of the second snow‐melting observation. (a) Asphalt mixture containing MF; (b) Asphalt mixture containing Mg₂/Al‐Ac⁻ LDH; (c) Asphalt mixture containing Cl⁻DIA; (d) Asphalt mixture containing MF after 4 hrs; (e) Asphalt mixture containing Mg₂/Al‐Ac⁻ LDH after 4 hrs; (f) Asphalt mixture containing Cl⁻DIA after 4 hrs (Peng et al. 2015).
3. Figure 18.3 Typical pavement section of a hydronic snow‐melting system (a) plan view, (b) cross‐section view (Yu et al. 2016).
4. Figure 18.4 Heat transfer mechanisms: (a) conventional bridge; (b) heated bridge (Yu et al. 2016).
5. Figure 18.5 Schematic principle of thermochromic‐based asphalt (UV = ultraviolet) (Hu 2016).
Chapter 19
1. Figure 19.1 Logic model conceptual diagram.
2. Figure 19.2 Scatterplot of prewet rate vs. normalized cost.
3. Figure 19.3 Iowa Department of Transportation Salt Dashboard. The graphs and time‐menu are interactive and allow users to zoom the data to their desired resolution.
Chapter 20
1. Figure 20.1 Percent of bare pavement and temperatures over time (hrs) from salting.
2. Figure 20.2 Phase diagram of aqueous salt binary solution.

Foreword

Wilfrid Nixon

Mobility is a critical part of modern society. Economies depend on the ability to move goods in a reliable and predictable manner and without this ability, economic output is severely degraded. People want to be able to move freely and thus require an effective and efficient transportation infrastructure to do so. Unfortunately, weather sometimes impacts the transportation system in such a way that it does not provide mobility and safety for goods and the traveling public. Transportation agencies, who are tasked with providing safety and mobility on the transportation system, thus undertake a variety of operations to maintain the safety and mobility of the transportation system even when the weather is less than ideal.

The economic impacts of a snow storm can be substantial. A variety of studies have considered the economic impacts of roads being closed (by, for example, a winter storm) across a state, and indicate that the economic cost of such a closure are between $300 and $700 million per day. And each year winter weather is a factor in crashes killing about 1,300 people. So good winter maintenance can clearly play an important role in providing safety and mobility for the traveling public.

This book aims to collect in one place all the information and understanding pertinent to conducting operations intended to ensure safety and mobility on the transportation system when that system is impacted by winter weather of all types. This foreword attempts to set this information and understanding in some sort of broad‐brush context. Obviously, the details are in the main chapters of the book itself. The foreword is an enticement to dip into the chapters!

Over the past thirty years there have been significant advances in the practice of winter operations, and in our understanding of how those practices can be made more effective. A key part of this advancement has been the understanding, which has grown in the past decade, that the practice of winter operations not only has to be sustainable, but has to be seen to be sustainable. For the most part, those involved in the practice of winter operations have inevitably balanced societal, economic, and environmental needs. The goals of winter operations almost require that such a balance be sought after and achieved. However, while the practice has been sustainable, the language describing that practice has been less so. It is important that both the practice and the language of the practice be seen to be grounded in sustainable processes.

Given the focus of this text on sustainability it is important to consider what exactly sustainability means and how applicable it is to winter maintenance. The standard definition of sustainable practices is as follows:

Sustainable operations meet the needs of the present without compromising the ability of future generations to meet their own needs.

Unfortunately, this is not particularly helpful when it comes to winter maintenance operations. For example, snow plows are not mentioned at all! The definition does not touch upon some of the very important research done on materials we use in winter maintenance, such as NCHRP Report 577. And quite frankly, the definition is sufficiently vague that it could mean almost anything depending on what you want it to mean. For example, what do we mean by “needs?” And what will “compromise the ability of future generations?” The danger with the vagueness is that not only does it lack guidance but it allows interpretation that can vary hugely.

One particular aspect of sustainability that is especially pertinent to winter operations is the so‐called triple bottom line. This approach suggests that rather than simply consider cost as the driving concern in operations, we should also consider societal needs and environmental impacts as having, if not equal weight, a similar weight in importance to budgetary concerns. In our field societal concerns relate to providing safety and mobility for the traveling public. Our environmental concerns relate to minimizing impacts on the environment. The latter is interesting because while, for example, using materials such as road salt does create a loading on the environment, so too does NOT using road salt. We know from a variety of studies that a well‐designed and implemented winter maintenance operations program will reduce crashes by between 85 and 90%. And each and every crash is a small‐scale environmental disaster – not only will various liquids (gasoline, diesel, engine oil, coolants and so forth) be spilled, but we will also have to replace the vehicles involved (not all the time, but it seems that even a small‐scale crash can lead to a vehicle being written off), which carries material and energy costs with their own environmental issues. So, good environmental stewardship may require us to use road salt (in suitable amounts and under the correct conditions).

Another aspect of sustainability that is not captured by the standard definition is what I call the “one size does NOT fit all” consideration. Not every community has the same needs and expectations when it comes to winter maintenance. Not every agency needs to plow residential streets for example. Many cities and towns in Colorado do not plow residential streets unless there is a large snow accumulation (in some cases, as much as ten inches) because in most winter events the snow is melted by the following day. It is a truism that the weather is different all across North America, so having the same approach to winter maintenance in Toronto and in Atlanta does not make much sense.

This book deals with the various aspects of winter maintenance operations and of course does so on a chapter‐by‐chapter basis. While each chapter is to some degree a stand‐alone document, it is not the intent of the book to suggest that there is no interaction between the various issues addressed within. Another aspect of sustainability when it comes to operations is to recognize that operations are part of a system and that each part of the system can impact other parts. Thus, by way of a simple example, the weather forecast should impact material application rates, but so too should the current pavement condition, and the traffic levels on a given segment of road. If the book becomes a collection of “silos” of knowledge, it will have not succeeded in its aims.

In conclusion, winter maintenance operations are critical to the safety and mobility of our transportation systems. Equally, those operations must be conducted in a safe and sustainable manner. This book aims to detail how such operations can be conducted in such a way.