Bridge Prioritization for Installation of Automatic Anti-icing Systems in Nebraska

During severe winter conditions bridges freeze before the surrounding roadways, often catching unsuspecting drivers off guard. Depending on weather and pavement conditions, automatic bridge deck anti-icing systems spray chemicals that prevent or minimize ice bonding to the pavement. The Nebraska Department of Roads (NDOR) is interested in installing such systems on various bridges statewide. However, the presence of 2,193 bridges in Nebraska and availability of limited funding required candidate bridge prioritization for installation of automatic anti-icing systems based on relevant criteria. This research was undertaken with the objective of developing a decision-aid tool that could aid NDOR with the prioritization of bridges for installation of automatic anti-icing systems. The authors reviewed literature on automatic bridge anti-icing systems and the experiences of various transportation agencies. Factors considered important in the installation of automatic antiicing systems included: accident history, bridge alignment, weather, traffic, and bridge distance from maintenance yard, among others. A methodology to build a database of relevant factors and a decision-aid tool that helped with narrowing the list of candidate bridges was developed. Database construction involved merging information from a variety of disparate sources in a geographic information system on factors deemed important in prioritization of bridge deck antiicing system installations. Some of the sources included NDOR bridge inventory, NDOR accident database, archived weather data from the High Plains Regional Climate Center and the National Weather Service, Nebraska streets database, Nebraska rivers and streams database, and NDOR maintenance yard data. Four different decision-aid methods were initially incorporated in the decision-aid tool: benefit-cost ratio, cost-effectiveness, utility index, and composite programming. However, subsequent research indicated that for various reasons, the prioritization results from the four methods were not suitable for Nebraska. As such a fifth method, called the NDOR Preferred Method, was developed in close consultation with the project’s technical advisory committee. The prioritization results from this method were accepted after extensive scrutiny. The data integration methodology and the processes developed in this research should be useful to other transportation agencies contemplating a methodical approach to installation of automatic bridge deck anti-icing systems for highway safety enhancement.