All drivers have individual ways of driving. Still, there are groups of drivers with more or less similar characteristics. In this research, 28 drivers from Chengdu city (P.R. China) participated in an experiment where car following behaviour was measured with GPS devices. In every measured trip there was a leading and following vehicle both equipped with a GPS device. Drivers are classified based on a Driver Behaviour Questionnaire and observed acceleration and deceleration behaviour. The result shows four distinct classes of drivers: macho drivers, careful/inexperienced drivers, smooth going/ professional drivers, and experienced/fast drivers. Drivers in the different classes give different emission of air pollution and fuel consumption. Saturation flows are determined from the trajectories and vary between different driver types. The measured trajectories have been analysed in detail to determine some parameters for the Wiedemann 74 model. Most default parameters in the VISSIM program appear to be unsuited for the simulation of driving behaviour measured in the experiment. The emissions and fuel consumption calculated by a simulation model with default parameters are not consistent with the empirical data. The calibration done for different driver types shows that several model parameters are significantly different for the different driver classes.