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Accurate calibration of material application equipment is the primary means through which a transportation agency can avoid overapplication of salt and other winter maintenance materials to counter snow and ice on roadways. Methods of effective calibration for salt spreaders have been examined extensively and presented in many published reports and manuals. Manufacturers include comprehensive guides with their equipment. Thus, instruction and guidance is widely available. Clear Roads member agencies were interested in learning more about calibration accuracy of equipment over time: the practices and experiences of agencies that could help identify factors that may diminish calibration accuracy of equipment over weeks and months of use in extreme conditions. Through a literature search and a survey of Clear Roads member departments of transportation (DOTs) and others, this synthesis gathered information about the types of material application equipment that agencies use, schedules and methods of calibration, training protocols, respondents’ perceptions of the accuracy of equipment, and types and qualities of materials.

Anti-icing (also known as “pre-treating”) is the winter road maintenance practice of applying a liquid or solid material intended to depress the freezing point of water in order to prevent winter storm precipitate from bonding to roadway pavement. Anti-icing may be performed hours (or even days) before a winter storm event begins; it can also be performed after ice or snow begins to fall in order to keep pavements as clear of ice and snow as possible. Salt [sodium chloride] brine and other chloride liquids are widely used for anti-icing. Historically, materials other than liquids, such as dry and prewetted salt/solids, have also been used by winter maintenance agencies for anti-icing. This Clear Roads synthesis project sought to learn how and the extent to which agencies use prewetted salts/solids for anti-icing, the conditions under which they are used, their effectiveness, cost-effectiveness and agencies’ response to environmental concerns about anti-icing salt use. The investigation included a national survey of state department of transportation winter maintenance experts that gathered information about materials used for anti-icing, including reasons why materials were selected, how they were prepared and applied, and their effectiveness, with particular focus on the use of prewetted solids. The results of a literature search supplemented the survey findings.

As a winter storm approaches, timing the activation and deactivation of winter maintenance operations has a significant impact on safety and budgeting. This synthesis report focuses on state practices in winter maintenance fleet activation for winter storms. A literature review and a survey of 25 Clear Roads states indicates that most agencies summon half or more of their workforce to come in before a storm arrives, if only just before. Meteorologists have become increasingly involved in winter maintenance programming, and a broad range of sophisticated systems, weather data and forecast sources are drawn upon in activation decisions, which are usually made at the district or regional level. Activation and deactivation procedures are data-heavy activities. Fleet activation practices seem equally informed by current and forecast data. Many states have specific thresholds (fixed numbers) for air temperature, pavement temperature, precipitation levels and other factors that trigger activation. Decisions about when to deactivate forces (send crews home) tend to be driven by a combination of fixed value thresholds and field observations. Current conditions are given more weight than forecasts, with the significant exception of precipitation forecasts. The increasing role of meteorology in winter maintenance activities suggests they may be becoming more data-driven.

An often-overlooked aspect of winter maintenance operations is snowplow operators’ risk of a crash. The goal of this project was to examine key causes of collisions involving snowplows, identify defensive driving strategies snowplow operators can use to prevent crashes, and develop two comprehensive and engaging snowplow operator training modules on safe and defensive driving. Questionnaires, interviews, and crash data were used to develop the two modules to provide snowplow-specific information that operators can use to prevent crashes. The first module includes strategies the snowplow operator can use to prevent crashes caused by another vehicle. The second module focuses on general safe driving practices that the operator can use to prevent crashes often caused by the snowplow operator. Winter maintenance agencies can use the modules to help snowplow operators become better defensive drivers and avoid collisions with other vehicles and objects.

This research brief was created as part of Clear Roads project CR 18-01, "Defensive Driving for Snowplow Operators," published June 2020.

This presentation was created as part of Clear Roads project 18-01, "Defensive Driving for Snowplow Operators," published June 2020

This presentation was created as part of Clear Roads project 18-01, "Defensive Driving for Snowplow Operators," published June 2020

The project began in the summer of 2019 and was completed in the winter of 2023. In this project, the research team investigated the wear of snowplow blades using three different sampling techniques. The first technique was large scale sampling that was completed in Idaho. The second sampling technique was small scale sampling that was completed in Norway. The third sampling technique was laboratory testing of individual snowplow blades. The results of this study provide the end user with a standard test protocol for testing snowplow blades. While the sampling size was limited, the results suggest that each of this sampling techniques are effective in measuring the wear of a snowplow blade.

This research brief was created as part of Clear Road project CR18-02, "High Performance Blade Evaluation," published January 2023.

This quick reference guide was created to accompany Clear Roads report CR18-02, "High Performance Blade Evaluation," published January 2023.