Before-and-After Empirical Bayes Evaluation of Achieving Bare Pavement using Anti-Icing on Urban Roads

Abstract

Canadian municipalities are increasingly choosing to achieve bare pavement (BP) for snow and ice control during fall/winter seasons. When a snowstorm event is forecasted, one strategy is to apply anti-icing chemicals to the pavement surface to prevent the snow and ice from forming a bond with the road surface. Such an approach facilitates a more efficient plowing operation and reduces the amount of deicing chemicals needed to achieve BP. This study assesses the safety performance of achieving BP using anti-icing compared with the traditional reactive winter road maintenance (WRM) approach on urban roads using the before-and-after Empirical Bayes technique. Results suggest that achieving BP significantly reduces all collision types and severities on midblocks with a reduction value in the range of 13.7% to 19.7%. Attaining BP at intersections was found to be very effective in reducing injury collisions with an estimated reduction of 12.5%. When sites were grouped based on a WRM priority-basis, it was found that anti-icing was effective for reducing the majority of collision types and severities at the different priority levels with reductions ranging from 8.7% to 49.83% on midblocks and between 5.37% and 13% at intersections. All reductions were statistically significant. The monetary benefits of the reductions in property-damage only and nonfatal injury collisions were estimated at 60 million Canadian dollars using a 1.92% interest rate and a 2-year service life. These findings provide unequivocal evidence that achieving BP using anti-icing can lead to significant societal safety benefits that economically translate to huge collision cost savings.