Deicing salt is used to avoid ice or snow on road surfaces and to facilitate snow clearing. For ecological and economical reasons wet salt should always be used; dry salt represents an adequate alternative only in very few circumstances and even then wet salt can be used without any disadvantages. As short a time as possible should elapse between ice formation and salt spreading. This can be accomplished by improving the regional meteorological service and by routing optimization. In the interests of safety, common economic and traffic regions, e.g. the EC-member countries, demand identical levels of service as far as winter service is concerned. Investigations conducted by Darmstadt Technical University have shown that the accident rate after spreading deicing salt falls approximately to one-third ofthe values recorded before road clearance commenced. In the Federal Republic of Germany (without the five new states) during one winterperiod some 1,000 deaths or serious injuries, approx. 1,500 slight injuries and some 6,000 accidents with material damage could be avoided within one hour after deicing salt being used outside built-up areas (excluding motorways). The theoretical assumption that motorists drive considerably more slowly on slippery roads, thus obviating the need for deicing salt, is not verified; evidence shows that speeds are reduced, but not to the extent required to compensate for the lower friction coefficient. The accident figures increase substantially in cases where no deicing salt is used. The number of injuries suffered by pedestrians has increased considerably in areas where deicing salt is not permitted on footways. Long-term ecological investigations at Giessen University, have revealed that no systematic damage to roadside shrubs outside build-up areas can be determine. It is only on motorways that the larger amounts of salt spread give rise to individual cases of salt induced damage to plants at a distance of up to approx. 10 m from the edges. These almost exclusively involve contact damage, which does not lead to an accumulation of chloride in the plant. The occurrance of such cases can be reduced to an acceptable level by an apppropriate choice of plants and locations, suitable plant care, structural measures and optimization of winter service. The importance of protecting life and health of persons by theuse of deicing salt, in conjunction with economic benefits, outweigh the negative effects on roadside shrubs that suffer avoidable or repairable damage locally in very few cases.
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