In 1985 the Swedish National Road Administration (SNRA), the Swedish Association of Local Authorities and the Swedish Road and Traffic Research Institute were commissioned to initiate a research programme with the objective to reduce the negative effects of winter salting without detracting from traffic safety and traffic ability. The programme titled MINSALT has been running for 5 years and will be completed with a final report in June 1991. "MINSALT" was divided into three part: a) Extension of salt-free regions and roads, b) New deicing method, c) New deicing strategies. Extension of unsalted regions included major experiments in three different parts of Sweden. On Gotland, an island in the Baltic Sea, both rural and urban roads were left unsalted from winter 1986/87 and onwards. In another county, Dalarna, the road network where salt was used were reduced during two test winters and the third test were performed in 50 km of road E4 in the northern part of Sweden. The aim of the three tests was to make a comparison of accidents, road conditions, corrosion, environment, road user opinion, road maintenance costs etc. when going from chemical deicing to winter maintenance without salt. New deicing methods included studies of more effective salt spreading. The methods of pre-wetted salt and spreading of salt solution were tested with mostly positive results. The methods have been used primarily for preventive actions and in situations with hoar frost and thin ice. Due to mild winters there are still some questions about the applicability in more severe weather situations like heavy snowfall. New methods also included tests with alternative chemicals. Among others calcium magnesium acetate (CMA) was tested as regards spreading, deicing, corrosion to metals and effect on cement concrete. New deicing strategies included the development of road weather information system and the use of de-icing or anti-icing measures at critical locations. An experiment with salt spreading only in junctions and just before these has been carried out in a town. So called "Ice-retardant overlays", rubber asphalt RUBIT and Verglimit, with salt, have been tested at a test road in the south of Sweden. The comparison was made to conventional asphalt concrete as regards skid resistance (especially in wintertime), wear, economy etc. (A)
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