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Chapter 8 (Revised August 2013)
Winter Operations and Salt, Sand, and Chemical Management
8.3. Strategic Planning for Reduced Salt Usage

8.3.1 Salt Management Plans
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Salt management plans (SMP) provide maintenance agencies with a strategic tool to effectively manage salt practices while maintaining its obligation to providing safe, efficient and cost-effective road management. Salt Management Plans apply to all winter maintenance staff and personnel (including hired contractors), and protect the people and the environment (TAC, 2003). Key components of a SMP may include:

  • A statement of policy and objectives
  • Situational analysis - on road use, salt vulnerable areas, sand and salt storage sites, snow disposal sites, training, etc.
  • Documentation
  • Proposed approaches
  • Training and management review.

A successful SMP may feature the following:

  • It is based on policy with guiding principles from a high-level organization.
  • It is activity based, with each activity assessed at the outset against clearly established standards or objectives showing minimized environmental impacts.
  • Deficiencies in current operations are identified and corrective actions are established and implemented.
  • Required actions are documented in policies and procedures and communicated throughout the organization.
  • Activities are recorded, monitored, audited and reported periodically to assess the progress and identify areas for further improvement.
  • Gaps between actions and desired outcomes are identified and corrective actions are developed and implemented, with necessary modifications made to policies and procedures and appropriate training.
  • The review cycle continues on an ongoing basis.

The City of Windsor, Ontario specified responsibilities of each personnel in a SMP as follows:

  • Executive Director, Operations - Has corporate responsibility for the SMP.
  • Maintenance Manager - Ensure that the SMP is developed, maintained, and implemented consistently across the organization. Oversee the maintenance and upgrading of the winter maintenance facilities in compliance with the SMP.
  • Fleet Manager - Purchase, maintain, and calibrate the winter maintenance fleet in compliance with the SMP.
  • Coordinator/Supervisor/Foreman - Ensure that winter maintenance activities are carried out in compliance with the SMP.
  • Winter Maintenance Personnel - Carry out winter maintenance duties in accordance with the policies and procedures set out in the SMP as directed by their manager.
  • Technical Support Manager - Assist in the development of methods to compile performance measures in compliance with the SMP (City of Windsor, 2005)

Salt management plans can also be used during the new road design and construction stages. For a highway-175 extension in Quebec, Canada, the developmental plan considered existing maintenance operations and developmental means and established objectives to reduce the impacts of road salts during design and construction (Tremblay and Guay, 2006).

From basic SMP guidelines agencies can make modification to address their specific budgets, and climatic and road conditions. One such improvement by the City of Toronto, Canada entails innovative salt management practices, such as: implementing electronic salt dispensers to control the salt flow, mixing sand into the salt when conditions permit, and pre-wetting the road salt (Welsh, 2005).

8.3.2 Winter Maintenance Effects on Safety and Mobility
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Highway winter maintenance activities offer such direct benefits to the public as fewer accidents, improved mobility, and reduced travel costs. For a 30-mile roadway segment in Iowa, accidents increased by 1300% and traffic volume decreased by 29% during severe winter weather events (Knapp et al., 2000). Another case study in 1992 found that costs related to accidents decreased by 88% after application of deicing salts (Kuemmel and Hambali, 1992). Studies in both Canada and United States show that on average, winter driving requires 33% more fuel (TAC, 2004). Indirect benefits of snow and ice control operations include: sustained economic productivity, reduction in accident claims, continued emergency services, etc. More importantly, the economy cannot afford the risk of shutting down highways in the winter. In 1996, a 4-day blizzard shutdown much of the northeastern United States and led to loss in production estimated at $10 billion, let alone accidents, injuries or other associated costs (Salt Institute, 2005).

Qiu and Nixon (2009) and Qui (2008) developed a method to measure the performance of a winter maintenance programs with respect to the provision of safety and mobility to motorists. The researchers noted that many past studies did not evaluate winter maintenance outcomes while accounting for factors including storm severity, road characteristics and maintenance efforts. To address this, a storm severity index was developed, with the effects of weather and winter maintenance on road surfaces estimated by Multinomial Logistic Regression (MLR). A Multiple Classification Analysis (MCA) was applied to estimate the contributions of winter maintenance to safety, including the use of products. Products included sodium chloride solution (brine), calcium chloride solution, or granular salt (application rates were only available for brine and calcium chloride). Results of the MCA indicated that the chemical variable was a strong indicator of property damage only (PDO) crash probabilities; the impacts of specific chemical types were not broken out (Qui, 2008). However, winter highway maintenance operations collectively (plowing and chemical use) were found to be a weak predictor of crash severity. For this analysis, the researchers found that maintenance operations indirectly impact safety through reducing snow/ice surface conditions (Qui and Nixon, 2009). Qui and Nixon (2009) also found plowing to have a more significant impact on increasing vehicle speed (improving mobility) than chemical treatment. Winter maintenance practices in general had a positive effect on traffic volume.

Fu et al. (2006a) examined the effects of winter weather and maintenance treatments on safety. Daily accident data, weather conditions and maintenance operations data were examined for two provincial highways in Ontario, Canada. It was found that anti-icing and pre-wetting operations improved safety on one study route (anti-icing was used on only one study route), while sanding operations had a positive effect on safety on both routes. The researchers noted that the safety effect of plowing and salting operations could not be statistically confirmed by their work, noting that there could be inter-dependencies between maintenance operations and snow conditions, with more maintenance operations dispatched during more severe weather conditions. Consequently, the variation in these operations under a given weather condition may have been small.

Fu et al. (2006b) performed a statistical analysis on observational data to identify the quantitative effects of weather and maintenance operations on snow melting trend. Products included rock salt with and without pre-wetting liquid, salt brine, liquid calcium chloride (corrosion inhibited), and liquid magnesium chloride (corrosion inhibited). The test site was a 50 km (31 mile) route on Highway 21 in southwest Ontario, Canada. The researchers noted that historically, quantifying the effectiveness of alternative winter maintenance treatments was a challenge due to the large variations in observational environments including weather, traffic and location. To address this, multinomial logit models were employed to capture snow melting outcomes under these conditions. The primary findings of this work were that pre-wetted salt outperformed dry salt by a reduction in snow cover from approximately 18% to 40%, CaCl2 was found to be much more effective as a pre-wetting agent and outperformed MgCl2 by approximately 10% to 71%, and was also more effective than salt brine (NaCl). While these findings were not directly tied to safety (or operational) performance, they do present insight into the effectiveness of different deicers in achieving snow melt, which has potential safety and operational benefits.

Kuemmel and Hanbali (1992) performed a simple before and after analysis on the effectiveness of salting on safety in New York, Minnesota and Wisconsin. The researchers found a significant reduction in crashes following salting operations, with an 87% reduction observed on two-lane undivided highways and a 78% reduction on freeways. However, the influence of weather-related factors and other maintenance activities (e.g., plowing) were not included in the research and could have resulted in an overestimate of the true contribution of salting.

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Continue to Section 8.4 »
 
Table of Contents
 
Chapter 8
Winter Operations and Salt, Sand, and Chemical Management
8.0 Introduction
8.1 Selecting Snow and Ice Control Materials to Mitigate Environmental Impacts
8.2 Reducing Sand Usage and Managing Traction Materials
8.3 Strategic Planning for Reduced Salt Usage
8.4 Stewardship Practices for Reducing Salt, Sand and Chemical Usage
8.5 Precision Application to Manage and Reduce Chemical Applications
8.6 Monitoring and Recordkeeping
8.7 Winter Operations Facilities Management
8.8 Training for Salt Management and Winter Maintenance Operations
  References
  Appendix A - Acronyms
   
Lists: Examples | Tables | Figures
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