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Evaluation of Storm Severity Index (SWI) and Winter Severity Index (WSI) Variables

Started: May, 2019 End Date: April, 2020 Project ID #4W7797 Status: Ongoing


The objective of this project is to identify agencies using SSI/WSI, determine the variables and measurement methods used to create the indices, and recommend variables to use and calculation methods.


Winter maintenance agencies can use a Storm Severity Index (SSI) or Winter Severity Index (WSI) as tools to help evaluate the performance of their maintenance crews and to plan for the efficient use of materials and other resources. In the last decade substantial work has been completed to develop nationwide  and statewide  SSI/WSI tools. From these past and ongoing projects the key variables, methods, and calculations can be used to aid in the development of a tool to help transportation agencies develop and use their own SSI/WSI. This project seeks to learn more about past efforts to create the SSI/WSI, to evaluate these past efforts on their reliability and correlation to severity, and to work toward creating a tool to guide jurisdictions when they develop their own SSI/WSI. Planned tasks include a literature review, a survey of practice, data collection and analysis, development or recommendations, and creation of a spreadsheet tool. WTI is providing project support to The Narwhal Group, which is the lead agency. The project is sponsored by the Clear Roads research program.


  • Laura Fay - PI

  • Chris Albrecht - Main External Contact

Sponsors & Partners

  • Clear Roads Winter Highway Operation Pooled Fund Sponsor

Part of: Cold Climate Operations & Systems

Project Tagged In: winter maintenance, severe weather

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