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The reliability of variables used in the calculation of storm severity indices or winter severity indices (SSIs/WSIs) was evaluated via an expansive literature review, an international survey, and two rounds of interviews with data and device managers. A Recommendations Guide was created to help agencies who want to improve upon or build anew an SSI/WSI; and included a thorough outline of reliable data, data sources, and SSI/WSI calculation methods. A spreadsheet tool was built that guides a user through the process of choosing variables and methods to address their predominant weather concerns.

The appendices for Clear Roads report CR18-03, Evaluation of SSI and WSI Variables," published December 2020.

The goal of this project was to aid winter maintenance managers in better understanding the performance and impacts of alternative methods for deicing, which may be non-chloride based deicers, blends of deicing products, or methods that reduce the number of applications or application rates of deicers. To achieve this, a literature review, survey, and follow-up interviews were used to develop case studies and recommendations on automatic vehicle location (AVL), blended liquid deicing products, direct liquid application (DLA), pre-wet, slurry, mechanical snow removal methods (ice breakers, squeegee plow blades, brooms, sweepers, segmented plow blades), methods to reduce chloride use, route optimization, salt alternatives, and using data to make informed decisions (severity indices (WSI, SSI, SWI), MDSS, and dashboards). Recommendations for implementation and successful use of each case study topic are provided, followed by recommendations on how to do a lot with a little, or how to identify and implement easy and low-cost improvements. This is followed by a section on making larger investments to find improvements. These sections provide examples, identify pros and cons, and review the challenges of going from being good at something to great. Key steps for implementation are identified, and training resources are provided. Research needs and gaps are identified related to alternative methods for deicing.

A refined return on investment (ROI) methodology is explored to supplement existing benefit-cost analysis (BCA) tools; data; and methodologies available to evaluate MnPASS managed lane projects. This would also facilitate more consistent and standardized measures for MnPASS system assessment and comparison. In this study; researchers investigated a more comprehensive set of factors; variables; and perspectives to include within the refined ROI analysis framework based on the limitations summarized in the current MnPASS BCA methodology; the major concerns identified from agency staff interviews; and available data resources. The selected cost components included initial capital costs; annual operating and maintenance costs; remaining capital value; and the potential benefit components consisted of travel time savings; vehicle operating cost savings; safety benefits; travel time reliability; transit benefit; induced traffic; emergency response; emissions impacts; and noise impacts. Tractable calculation methods were further explored for each cost and benefit measurement in order to facilitate use of the economic analysis tool. To verify the performance of the proposed methodology; the research team conducted a comparative demonstration; which produced a higher benefit-cost ratio than previous work. Furthermore; the contributions from additional benefit considerations highlighted the importance of integrating a wider range of project impact categories in the MnPASS ROI analyses.

The objective of this project was to develop materials to aid winter maintenance practitioners in making informed decisions on the use of road salts, specifically sodium chloride. To accomplish this, a detailed literature review was conducted, followed by a laboratory investigation that monitored ice formation and precipitation of salt at various concentrations and temperatures. Using the information collected through the previous tasks, a one-page fact sheet and educational video were developed to aid winter maintenance practitioners in how to use and apply information shown in salt phase diagrams. Results from the lab testing produced great images and video of ice and salt crystal formation in solution. Limited ice crystal data was collected and analyzed. Detailed ice crystal formation results could provide significant information to advance this topic. Images of ice crystals with bubbles, potentially filled with salt brine, indicate that the solid phase of ice crystals and salt crystals is not pure, implying that many phases can co-exist. This reinforces the concept that ice formed in the presence of salt brine is weaker than ice formed only in the presence of pure water. When measuring pavement friction following the application of salt brine at various concentrations, the results varied between pavement type, salt concentration, and friction measurement technique. There is value in further refining this, or another, performance test method to assess the influence of salt brine concentration on pavement friction.

Various costs and benefits are incurred while performing winter maintenance operations. However, a summary of these costs and benefits for different maintenance scenarios has not been compiled to date. This report summarizes past work that documented the quantified and non-quantified costs and benefits of three different winter maintenance strategies of interest; use of abrasives, salts and other chemicals in solid and liquid forms, and snow plows. Basic strategies were defined as plowing and use of abrasives, intermediate strategies were defined as the use of rock salt and salt brine (NaCl), and advanced strategies were defined as the use of corrosion inhibitors, inhibited salt brine, magnesium chloride, calcium chloride, and blended products. These approaches employ different components, both in terms of equipment as well as materials. Some components of the various strategies have better cost and benefit information available than others. This is particularly true of sanding/abrasives and salting. Other, more recently developed and employed approaches and materials have more limited cost and benefit information published. There are also a number of different environmental impacts associated with different components of each maintenance strategy. Using information gained from the literature review, surveys, and interviews summary benefit-cost matrices were developed for various winter maintenance strategies. Information and data gap analysis has aided in identification of areas for recommended research. This document is intended for use by transportation agencies, such as by maintenance supervisors, to aid in the decision making process in terms of the selection of winter maintenance strategies used to achieve a prescribed LOS.

This document is the final report for the Clear Roads project entitled Best Practices for the Prevention of Corrosion of Department of Transportation Equipment: A User’s Manual. The project team was led by researchers at the Western Transportation Institute at Montana State University (WTI) on behalf of Clear Roads, an ongoing pooled fund research effort focused on winter maintenance materials, equipment, and methods. Clear Roads research projects are managed and administered by the Minnesota Department of Transportation (MnDOT). Through this project, the research team developed a user-friendly manual that documents best practices for managing the risk of equipment corrosion, especially in the presence of chemical deicers. The audience for this manual includes operators, mechanics and garage-level supervisors. The manual defines the basic corrosion conditions, with a focus on the need for managing corrosion risks, common modes of corrosion failure, and corrosion-prone parts (priorities) on DOT equipment. This manual addresses design considerations and material selection for corrosion risk management. This manual also lists some commercial products that have been used by DOTs, and presents some successful experiences of DOTs, the US Navy and private companies. It also presents preventive maintenance strategies and tactics.

On behalf of the Minnesota Local Road Research Board (LRRB); the Western Transportation Institute (WTI) at Montana State University (MSU) and the University of California Davis (UCD) developed A Guide to Successfully Convert Severely Distressed Paved Roads to Engineered Unpaved Roads. The guide serves as a comprehensive information source on effective practices for converting severely distressed paved roads to acceptable unpaved surfaces. This final report recounts the effort associated with the seven tasks involved in the completion of this project; the location of each task deliverable; and future research needs to advance this topic.

The goal of this research project was to analyze and make comparisons of the impacts of abrasives, chlorides, acetates, formates, glycerols, glycols, and organic by-products; and to compile the current environmental best practices for using chlorides. To accomplish this, a literature review sought information on the impacts of chemical deicers and abrasives and their associated impacts to air, surface and ground water, roadside soils, flora and fauna. The review also documented currently available knowledge of cost-effective equipment, practices, and strategies that allow snow and ice control operators to use the right amount of material in the right place at the right time, in an effort to achieve the “Triple Bottom line” of sustainability (economy, social, and environmental). A survey and interviews were used capture information from winter maintenance practitioners on the current state-of-the-practice, best practices, and lesson learned. The interviews were developed into Case Studies. The information captured in the previous tasks was further analyzed and processed into easy-to-use at-a-glance tables, which have been incorporated in to the manual. All of the information captured in the aforementioned tasks was used to create the Snow and Ice Control Environmental Best Practices Manual, the principal deliverable for this project.

A manual on environmental best management practices used for snow and ice control was developed using information gain from a literature review, survey, and follow-up interviews. The document presents information on commonly used snow and ice control products and their potential impacts, and pathways into the environment. Following this information is presented on many aspects of snow and ice control operations from material handling and storage, application techniques and equipment, advanced technology for decision making, environmental management tools, pre-storm to mid-storm practices, post storm clean-up, and training. The manual summarizes common areas for improvement in snow and ice control practices to realize material and cost saving, while reducing impacts to the environment.