The present work shows the ability of Navier-Stokes codes to handle detailed chemical kinetics models to compute the reactive and vibrational non-equilibrium gases in shock layers and the recent development done in our laboratories towards this goal. The detailed model used in the present study is a simplified version of a collisional-radiative model for N 2 that has been implemented step-by-step in a Navier-Stokes code in order to show the effect of each group of chemical and vibrational processes. The processes taken into account are the vibration-vibration exchanges and the vibration-translation exchanges through molecular or atomic impact, leading to dissociation or not. The question of how the vibrational levels reach the Boltzmann distribution is also assessed. Comparisons of results obtained with global and detailed chemical kinetics models are presented.