The fuel consumption of road vehicles is influenced by many factors. One of them is the acclerator position. Measurment of the fue lconsumption on a rollingstand was done for the quantification of this effect. The tested vehicle was Kia Cee´d with a petrol engine. The measurments were done in laboratory condiditons to give higher accuracy. The results describe the degree of the effect of the accelerator position. They can be used for the determination the position considering to the actual output power of the engine and for the detrmination of the correctly driver behavour. The correctly usage of the accelerator contributes to the reduction of environmental burden of transport.