Experiment with Reduced Salting of Rural Main Roads in Finland

Abstract

An experiment was conducted in the road district of Kuopio in the winters of 1992–1993 and 1993–1994 in which the use of salt in winter maintenance on rural main roads was reduced to 1 to 2 T/road kilometer from the approximately 10 T of salt that typically had been used per road kilometer in similar conditions in recent years. On the experimental roads, salting was replaced by sanding. The cost of winter maintenance on the experimental roads increased by 20 percent on average, and the increase was higher on roads with higher traffic volumes. Slippery conditions due to ice and snow on the road surface were twice as frequent (30 to 40 percent of the time) on the experimental roads as on the control roads in the neighboring road district. There were 27 injury accidents on the experimental roads in the first winter and 25 in the second. This was about the same as the average of the five previous winters. Because the accident trend on other roads in the same time was decreasing, it was concluded that the experiment increased the number of injury accidents by approximately 20 percent on most experimental road sections. Reduced salting decreased the sodium and chloride concentrations in the needles of roadside pine trees. There were also indications of decreased sodium and chloride concentrations in groundwater. Three quarters of the population in the area was pleased with the experiment.