Abrasives and Salt: New Research on Their Impact on Security,Economy,and the Environment

Research was performed to obtain an integral view of the effects of salt and abrasives spreading on security, economy, and the environment. In addition, the research was to provide objective and practical strategies and decision-making aids for the improvement of efficiency and economy in road winter maintenance. Findings with regard to security were that spreading of salt contributes significantly to traffic safety in winter and can be considered an effective solution for road safety. Abrasives, on the other hand, have a limited and normally only short-term effect on slipperiness. The adhesion of tires to the road surface, crucial for the braking distance and stability of the vehicle, is limited. Spreading of abrasives suggests a false security and entices the road user to drive faster than advisable. The risk factor increases considerably. As to economy, existing studies and experience show that salt spreading is highly beneficial. For abrasives, limited data could be found. Tests carried out during two winters in the Swiss cities of Zurich, Baden, and Chur showed that the costs for the use of abrasives are six times higher than those for salt in normal winters and 10 times higher in severe winters. In the case of environmental effects, the impact of salt on soils, flowing water, and underground water was found trifling because of the locally and temporarily limited appearance. The impact on vegetation, especially on roadside trees in urban areas, must not be underestimated. Measures to reduce the salt load are recommended. The use of abrasives produces waste. The ecology balance shows that with respect to energy and water consumption, waste, and emissions in air and water, salt comes off distinctly better than do abrasives. However, further efforts are necessary to reduce the amount of both substances used in road winter maintenance.