Enhancing Winter Weather Impact-Based Services by Utilizing Crash Data

Each year, traffic accidents from winter weather conditions lead to injuries and fatalities on roadways. Major disruptions to commerce and transportation occur as well. While expected accumulations of snowfall and other winter weather types are important to know and communicate, additional impact-based information improves confidence and aids in messaging when providing decision support services for potential impacts to society due to winter weather.

The Winter Storm Severity Index and the National Weather Service internal prototype Hourly Winter Storm Severity Index have been developed and utilized to communicate the spatial distribution and severity of anticipated societal impacts. This supplemental information aims to provide a graphical depiction of anticipated overall impacts to help users of the data better understand the threats of a winter system for planning purposes with the goal of mitigating winter weather hazards.

This study analyzes crash data in comparison to the output from the Winter Storm Severity Index and the prototype Hourly Winter Storm Severity Index in order to calibrate these indices to transportation impacts during a variety of winter weather events. A case event review is also examined to see how these indices are utilized in an operational setting in order to give confidence to messaging a situation where potential impacts on roadways due to winter weather are high even though predicted snowfall values are low. This review, along with the crash data comparison, provides valuable feedback for the enhancement of the Winter Storm Severity Index and the National Weather Service internal prototype Hourly Winter Storm Severity Index. In addition, it demonstrates how impact-based forecasting tools provide valuable supplemental information for the improvement of decision support services and increases confidence in communication of potential impacts with transportation partnerships such as the Federal Highway Administration Pathfinder program and with others.