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Many agencies use storm severity indexes and winter severity indexes to make comparisons between storms and across multiple winter seasons. But developing an effective severity index can be challenging due to the multitude of variables involved and the availability and quality of data. 

To help agencies find the right fit, a recent Clear Roads research project created a step-by-step guide to implementing a severity index and a flowchart tool that helps match users with existing indexes. Both tools help states assess the most feasible option: using or modifying an existing severity index or developing a new custom index.

Download the final report and appendices: Evaluation of SSI and WSI Variables, December 2020.

Image source: Utah DOT.

By preventing blowing snow from reaching the roadway, snow fences have proven to be an important tool for many state DOTs. In Illinois, two recent studies are helping IDOT refine its approach to snow fence design and better assess the fences’ cost-effectiveness.

A new benefit-cost analysis tool will help IDOT select locations for three fence types: living snow fences, structural snow fences and standing corn rows. For living snow fences, the research provides guidance on fence setback, orientation, height and porosity, as well as recommended plant species.

Read the research reports:

• Evaluating the Costs and Benefits of Snow Fences in Illinois: Phase 2, Illinois DOT, November 2020.
• Design of Living Barriers to Reduce the Impacts of Snowdrifts on Illinois Freeways, Illinois DOT, November 2020.

For more recent research on snow fences, see Reducing Uncertainties in Snow Fence Design: Development of Methods for Estimation of Snow Drifting and the Snow Relocation Coefficient, published by Iowa DOT in September 2020.

Image source: Iowa DOT

A recent Clear Roads research project developed standard procurement specifications for carbide-insert plow blades that any agency can download and use. Designed to help agencies acquire high-quality, long-lasting blades that consistently perform well on the road, the specifications also provide thorough guidance for independent lab testing and inspection of carbide inserts.

Download the specifications and final report: Standard Specifications for Plow Blades with Carbide Inserts, April 2020.

Image source: Massachusetts DOT

A step-by-step guide to spreader calibration is the latest addition to Iowa DOT’s popular Winter Operations Training video series. The 10-minute calibration video includes demonstrations on both granular and liquid equipment.

Updated in 2020, Iowa DOT’s training videos have long been a valuable resource for winter maintenance programs in Iowa and beyond. The series includes 14 short videos on topics such as plowing techniques, equipment checks and using weather resources.

Watch the videos: Iowa DOT Winter Operations Training Series, updated October 2020.

For more on this topic, see Clear Roads’ Training Resources and Spreaders Research pages.

Image source: Iowa DOT

Drivers on a stretch of Interstate 35 in southern Minnesota received advance warning this winter when snowplows were working nearby. In an effort to reduce crashes, Minnesota DOT pilot-tested technology that uses highway message signs to let motorists know when slow-moving plows are ahead on the highway.

Ten snowplows were outfitted with the technology, which activates the message signs as the plows pass. The signs display a warning message, such as “Snowplow ahead: Use caution,” that stays activated for several minutes. The pilot project is part of MnDOT’s connected and automated vehicle research.

Read the press release: “MnDOT tests I-35 snowplow activation of warning signs to boost safety,” January 2021.

Photo by David Gonzalez, Minnesota DOT

A recent Clear Roads synthesis project surveyed state DOTs about which spreader systems they use, what features the systems have, and how satisfied the agencies are with their systems.

Price, ease of use, and specific features were important factors in spreader selection, and most respondents reported being satisfied with their spreaders. The synthesis provides detail on agencies’ evaluations of their systems.

Read the synthesis report: Inventory and Use of Salt Spreading Systems, January 2021.

Image source: Michigan DOT

Clear Roads’ Qualified Products List (QPL) takes center stage in Episode 45 of AASHTO’s SICOP Talks Winter Ops podcast. Host Rick Nelson talks with Patti Caswell of Oregon DOT about the history and the future of the QPL, which was created by the Pacific Northwest Snowfighters consortium as a way to collectively test deicing chemicals and establish specifications for products that emphasize safety, environmental preservation, infrastructure protection, cost-effectiveness and performance.

The QPL is now managed by Clear Roads, which is nearing the end of a process to update procedures and product categories to make the QPL more transparent for both agencies and vendors. Caswell chairs the Clear Roads subcommittee that oversees the QPL.

Listen to the podcast: Episode 45: Qualified Product List for Deicing Chemicals, March 2021.

If you’re looking for the latest research and guidance on deicers, extreme weather, or any other aspect of winter operations, be sure to check the Transportation Research Board. A recent TRB article serves as a guide to the organization’s winter-related resources, including:

• NCHRP Research Report 889: Performance Measures in Snow and Ice Control Operations
• NCHRP Research Results Digest 387: Alternative Delivery Methods for Winter Maintenance Operations
• NCHRP Synthesis 449: Strategies to Mitigate the Impacts of Chloride Roadway Deicers on the Natural Environment

Read the article: Preparing for Winter Weather with Transportation Resources, March 2021.

Image credit: Washington State DOT

An ongoing plow route optimization effort at Delaware DOT is yielding benefits for state residents. By optimizing selected routes for mileage efficiency, the department has been able to reduce snow removal service times and improve its level of service.

DelDOT began its route optimization work in 2019 following a 2018 research project, and the agency is currently working to expand the effort to more areas. The agency’s successes with route optimization were featured in a recent issue of FHWA’s Every Day Counts newsletter.

For more on this topic, see Clear Roads’ Plow Route Optimization Research page.

Image credit: Delaware DOT

While not yet widely available, corn-based deicers have shown some promise as an environmentally friendly alternative that could reduce the use of salt.

Iowa DOT researchers conducted lab tests on a series of corn-based deicer blends—mixes of salt brine and three types of corn-derived alcohols.

They identified several combinations that performed well in terms of freezing-point depression, corrosion inhibition and ice-melting capacity. While cost and logistics issues must be explored further, the blends’ performance showed enough promise to warrant further study.

Read the final report and two-page research brief: Corn-Based Deicers, July 2020.

Image source: Iowa DOT