This work was done to determine the effect of a specially treated deicing salt on the rate of corrosion of various automobile metals when subjected to actual driving conditions.An undercar rack containing the panels was attached to vehicles in Minneapolis (treated salt) and Milwaukee (plain salt) for 14 weeks during the 1965-1966 winter. A description of the type of panels exposed and method of their evaluation is presented. On the basis of visual examination and statistical analysis, panels exposed in the Minneapolis area showed consistently less corrosion than panels exposed in the Milwaukee area. Weather data were the same for the two cities on the basis of critical corrosion temperature, humidity, and precipitation ranges.Water samples were taken from streets, effluent storm sewers, lakes, and rivers in Minneapolis and St. Paul and the hexavalent chromium and chlorides were analyzed. Results indicated that the levels of chromium and chloride in the waters were within the drinking water standard for potable water.