Winter Storm Event Volume Impact Analysis Using Multiple-Source Archived Monitoring Data

Abstract

Data collection and information management systems typically are implemented to improve decision-making efficiency and capabilities. Results of these systems sometimes are used in real-time scenarios; however, in other instances, the data are collected and summarized, then archived or possibly destroyed. Data from several information management systems in Iowa were used to analyze the traffic volume impacts of winter storm events. Roadway and weather condition data were acquired from a roadway weather information system, and hourly traffic volumes were obtained from automatic traffic recorders. Daily snowfall data were acquired from the Iowa Department of Agriculture and Land Stewardship and the National Weather Service. Winter storm events with at least a 4-h duration and snowfall at 0.51 cm/h (0.20 in./h) or more were evaluated. Overall, 64 winter storm events were defined and analyzed for seven interstate locations. The analysis indicated that winter storm events generally decrease traffic volumes, although the impact can vary greatly. The calculated average winter storm event volume reduction was approximately 29 percent, but ranged (by data collection location) from approximately 16 to 47 percent. Regression analysis revealed a statistically significant positive relationship between winter storm event percent volume reduction, total snowfall, and the square of maximum gust wind speed. This research can be used to determine the potential volume impacts of winter storm events and provide additional data for the eventual development of a winter-weather level of service system based on traffic flow characteristics.