  Several three-dimensional Unsteady Reynolds-Averaged Navier-Stokes (URANS)
simulations of the passing generic vehicles (Ahmed bodies) are presented. The
relative motion of vehicles was obtained using a combination of deforming and
sliding computational grids. The vehicle studied is an Ahmed body with an angle
of the rear end slanted surface of $30^{\circ}$. Several different relative
velocities and transversal distances between vehicles were studied. The
aerodynamic influence of the passage on the overtaken vehicle was studied. The
results of the simulations were found to agree well with the existing
experimental data. Numerical results were used to explain effects of the
overtaking manoeuvre on the main aerodynamic coefficients.
