The aim of our research was to find out the environmental polluting effect and the compound of heavy metals in the water running offthe surface of roads carrying heavy traffic.The heavy metal load on road surfaces comes from the engines and surfaces of vehicles and roadside At the 34 km section of highway M3 a sampling machine took samples of run-off liquid from the road surface every 10 minutes.The sampling was carried out during the whole period of running off.The samples were analysed and examined in an authorized laboratory.In the run-off liquid the following elements were found:zinc,cadmium,chromium,lead,manganese,nickel,copper and iron.The heavy metal concentration of the run-off water is the highest in the one-third period of precipitation,which decreases exponentially the following way:Fe>Zn>Cu>Pb>Ni>Cr>Mn>Cd.The surface run-off water is absorbed in the surrounding area.The chemical analysis of soil samples collected from this area also shows the contemination of run-off water.The heavy metal concentration of the absorbing area is significantly higher than that of the control area which is not polluted.An accumulation of heavy metals can be shown as the result ofabsorbtion.