Snow and ice control

These photos show a snowplow or snowplows actively plowing snow.

This research brief was created as part of Clear Roads project CR20-03, "Evaluation of Indoor Automated Stockpile Measurement Systems, published December 2022.

This spreadsheet collects the data gathered for Clear Roads report CR20-03, "Evaluation of Indoor Automated Stockpile Measurement Systems."

The goal of this project was to conduct a data-driven evaluation of currently available automated or semiautomated indoor salt stockpile measuring systems in order to improve agencies’ day-to-day management of their salt stockpile inventories. Based on the types of automated and semi-automated indoor stockpile measuring systems available, project need, and vendor willingness to participate in the project, the following systems and state sites were selected for the project: Stockpile Reports photogrammetry system at two sites in Texas and one site in Washington state, Carlson FiX1 lidar system at a site in Delaware, and Skydio drone analyzed by DroneDeploy software at the same site in Delaware. Comparable measurements were taken at these sites using Total Station optical surveying, FARO 3-D scanner surveying, and tape-and-wheel measurements and compared in controlled tests. Both the Stockpile Reports and Carlson FiX1 equipment appeared to work as presented by vendors and regularly produced stable and precise measurements with little or no effort required of state DOT staff after the equipment was set up. The Skydio equipment worked well but is not close to being an automated or semi-automated solution at this time.

This research Brief was created as part of Clear Roads project CR20-02, "Understanding the Salt Phase Diagram," published June 2022.

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.