Earth and Atmospheric Sciences, Department of


First Advisor

Dr. Mark Anderson

Second Advisor

Dr. Matthew Van Den Broeke

Third Advisor

Dr. Dawn Kopacz

Date of this Version

Spring 4-21-2021


"Analysis of Winter Weather Conditions and Their Relationship to Crashes in Nebraska" (2021). Dissertations & Theses in Earth and Atmospheric Sciences. University of Nebraska-Lincoln


A THESIS Presented to the Faculty of The Graduate College of University of Nebraska In Partial Fulfillment of Requirements For the Degree of Master of Science, Major: Earth and Atmospheric Sciences, Under the Supervision of Professor Mark R. Anderson. Lincoln, Nebraska: April 2021

Copyright (c) 2021 John Cecava


Adverse weather conditions: such as changes in visibility, precipitation, wind speed, temperature, and road surface conditions, substantially impact highway and interstate safety. Therefore, an investigation into the winter weather conditions during highway and interstate crashes in Nebraska was conducted. Crash data were obtained from the Nebraska Department of Transportation (NDOT) for the years 2008 to 2018. In order to separate the non-winter weather related crashes and the winter weather related crashes, six filtrations were applied to make this possible. These filters were based on a few crash parameters: road classification, alcohol, and crash severity, and weather parameters within the crash data: road surface condition, weather condition I and II. Once the filtrations were applied for all crashes in the study period, winter weather data were found for each crash. Different aspects of both crash and weather data were then analyzed to obtain insights into the impacts of Nebraska weather on roadway crashes. National Weather Service winter weather alerts were also examined to see what type and severity of alert was issued at the time of fatal crashes. When synoptic-scale storm systems are present, Colorado lows are more deadly and cause more crashes than Alberta clippers. In addition, winter weather advisories were the most common weather alert issued during a fatality. From this information, whenever Colorado lows are being forecasted as the storm type, the public should be put on higher alert due to the number of crashes this storm type causes. The characteristics of both of these storm types; including snowfall, wind speed, visibility, and temperature all change the impact of these storm types. Snowfall and high wind speeds result in blowing snow which reduces visibility, producing the most crashes. When looking at temperature only, most crashes occur when the temperature is around freezing, since the snow has a low snow to liquid ratio or due to re-freezing. Furthermore, the weather alerts need to continually improve on the impact‑based method to help reduce the number of crashes and crash severity. The public will continue to travel, especially when winter weather advisories are issued, until there is a more severe warning issued. Ultimately, this research will quantify weather related factors associated with motor vehicle crashes in Nebraska.

Advisor: Mark R Anderson