This paper illustrates the development and implementation of a parameter optimization methodology to improve impact harshness (IH) of road vehicles. A full ADAMS model of a small commercial vehicle is used as the IH test vehicle. The methodology involves the use of design of experiments methods together with response surface methodology. Significant design parameters affecting IH of the vehicle are first determined by the screening experiments. Once the critical parameters are identified, they are optimized to achieve improvement in the IH by constructing response surface. The optimization results indicate that the selected suspension parameters are capable of improving IH performance of the full vehicle ADAMS model by minimizing longitudinal and vertical acceleration responses. The results also show that considerable improvement can be obtained by using the proposed parameter optimization methodology.