Using steering stability theory, the way of optimization of vehicle parameters is given in this paper. A suitable mechanical model of vehicle movement including its basic characteristics is defined. Then a methodology of qualitative estimate of control stability is given through: stability conditions, reaction time at disturbances and vehicle steering. On the basis of the analysis performed by the authors the optimal criteria of control stability are defined. The system environment - vehicle - driver (E-D-V) is considered.To illustrate the given methodologies the influence of the mass on the steering stability is given in the paper.