Selection of Strategies for Winter Maintenance of Roads Based on Climatic Parameters

Abstract

The aims of the presentation are to discuss the efficiency of the different methods for friction control of winter roads on the safety and accessibility due to climatic conditions, to show that the climate should be an important factor in selecting the strategies for winter maintenance and to establish climatic parameters that may be helpful in making those decisions. The analyses are based on Swedish data assembled by VTI on road accidents involving fatalities and severe injuries, road surface conditions and climate. The accident and the road condition recordings are compared to self-defined climatic parameters, which describe the severity, stability and instability of the winter climate in the regions investigated. The parameters are assumed to describe whether salting or sanding is favorable/unfavorable for friction control. The results of the analyses show that the effect of salting is substantial for improving accessibility. Generally the number of winter accidents resulting in fatalities and severe injuries is lower on the salted road network compared to the unsalted road network in the southern and central parts of Sweden. However, in the northern region, with very cold winters, the number of winter accidents is highest on the salted road network. The data also indicates that the highest accident numbers are found when the proportion of vehicle mileage on snow and ice in the winters varies within 30–40%. The paper recommends that salting should be avoided in areas and in periods when the frequency of road surface temperatures below