Motor vehicles are a significant source of pollution of the natural environment. To reduce its adverse effects lead-free petrol and catalytic converters are gradually introduced on an increasing scale. Because of high costs, implementation of these measures will take a long time. In short term, quantities of toxic combustion products can be reduced by lowering fuel consumption. The article presents the factors which affect consumption of liquid fuels (technical, operational, road and traffic factors as well as driving style). Thus, reduction in liquid fuel consumption by motor vehicles will result in a decrease in fuel expenses, and above all, it will abate pollution of the natural environment, particularly in urban centres.