Highway Traffic Volume Variations with Cold and Snow Interactions

Present study investigates the traffic volume variations due to the interaction of sever weather conditions. The study is based on hourly traffic data from 350 permanent traffic counter sites located on provincial highway system of Alberta, Canada, and weather data obtained from Environment Canada weather stations located within 15 miles from the selected permanent traffic counter sites, during the period 1995-2005. Multiple regression analysis is used for the study analysis. The model parameters include three sets of variables: amount of snowfall as a quantitative variable, categorized cold as a dummy variable and an interaction variable formed by the product of above variables. The developed models closely fit to the real data with Rsquare values of above 0.99. The study results indicate that the impact of cold and snow on traffic volume varies with day of week, hour of day and adversity of weather conditions. Traffic volume on a day decreases with the increase in severity of cold and snow. A reduction of 1% to 2% in traffic volume for each centimeter snowfall is observed when the mean temperatures are above 0o . For the days with zero precipitation, reductions in traffic volume due to mild and severe cold are 1% and 31% respectively. An additional reduction of 0% to 3% per one centimeter of snowfall results when snowfall occurs during severe cold conditions.