This paper intends to analyze the simultaneous impact of speed and acceleration on exhaust pollutant emissions.For this purpose, actual driving recording were used. Kinematic sequences were randomly selected amongst the recorded data, in order to constitute a representative set of driving conditions. For each sequence, average levels of speed and positive acceleration were calculated. Instantaneous and integrated pollutant emissions were calculated using an existing emission model, developed for calculating pollutant emissions and fuel consumption as functions of instantaneous speed and acceleration. This model is based on instantaneous emission measurements on a chassis dynamometer using actual driving cycles, over a sample of 150 European cars.Emissions of CO, CO2, HC, NOx were analyzed considering the average speed and positive acceleration, for different categories of vehicles Diesel, conventional and catalyst vehicles.For all types of vehicle a significant influence of speed on emissions is observed. The acceleration impact seems to be less marked, except for the catalyst vehicles which show the strongest dependence upon acceleration.