This paper considers the flow velocities and the dispersion of pollutants in the wake o f a number of different types of ground vehicles. It does this mainly through a collation of the results of a number of experimental, numerical and analytical investigations carried out by the author and his co-workers over the last few years, and a comparison of these res ults with the work of other investigators. It is shown that the wakes of ground vehicles m ay be conveniently taken to consist of two regions: a near wake and a far wake. The near wake is characterised by large scale recirculation and longitudinal vortex structures, with unstea dy fluctuations caused by a variety of effects, including instability of the separated shear l ayer and wake pumping. In the far wake there are no discernible flow structures with a steady decay of the velocity field, with the major component of wake unsteadiness being at large scale s. The effect of cross-winds is to translate and diffuse the wake, with the balance between the two effects changing depending upon the nature of the surrounding topography. Only a rel atively few measurements have been made of dispersion within vehicle wakes, other than in t he rather complex case of vehicles in street canyons. However, there are a number of analytical solutions of wake dispersion that have, to some extent, been validated by comparison with full-scale experiments. On the basis of these investigations, it is suggested that the lower frequen cy fluctuations in vehicle wakes may have an effect on the dose of pollutants received by pedestrians at the roadside, and more work is suggested to quantify this further.