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DEVELOPMENT OF WINTER SEVERITY INDICATOR MODELS FOR CANADIAN WINTER ROAD MAINTENANCE

Abstract

This paper discusses the development of two winter severity indicator models that will be used to evaluate the relative harshness of a winter in comparison with a base period, by using meteorological data through the Meteorological Service of Canada (MSC) alone, and MSC data together with Road Weather Information System (RWIS) data. A winter severity index is a measure of the relative impact of winter weather on winter road maintenance (WRM) operations using historical meteorological or RWIS data. A review of past research led the project team to develop their own set of models using Canadian WRM, MSC and RWIS data. WRM data were collected from across Canada from a total of eight provincial road authorities and seven cities. Salt usage in tonnes (salt (t)/lane-km/day) was chosen as the dependent variable, standardized to account for differences in road network and the number of days in the observation period. The first model developed based on MSC data alone achieved a goodness of fit of 0.54. Explanatory variables were based on snowfall occurrence, air temperature, freezing rain occurrence, and an east-west dummy variable to account for differences in winter road maintenance practices in different parts of Canada. A second model was developed based on MSC data together with RWIS data. This achieved a goodness of fit of 0.60, but was based on a significant smaller sample size. In this model, pavement temperature was substituted for air temperature. An Index was developed based on the predicted values using a scale between 1 and 100. Calibration factors were developed for twenty different homogeneous groupings across Canada using the Bayesian method. Based on the calibration, thirteen of the twenty groups achieved a better goodness of fit compared to the national model results. The model results show a better performance in heavily populated areas and in eastern Canada. Limitations of the models and recommendations for further research are presented in the paper.

Conference Paper Details

Session title:
SUCCESS IN ROAD SALT MANAGEMENT
Author(s):
Suggett, J
Hadayeghi, A
Mills, B
Andrey, J
Topics:
Environmental issues, Environmental legislation
Year:
2006