Despite the seemingly daily development of high-strength new generation steel sheets, steel sheets still remain the most important engineering material used in a vehicle body. These steel parts in a vehicle body, meant to absorb energy during impact, are generally produced by steel forming methods. These steel forming operations may contain processes such as deep drawing, bending, cutting, spring back, spinning. According to the production conditions and type of processes used during the production of sheet metal parts, thinning, thickening, plastic deformation, folding, tearing and wrinkling may occur. In order to achieve more reliable impact simulations, these effects in the forming process should be conferred on impact analysis. Within the scope of this study, an analysis of the critical parts in steel forming that absorb the most energy during the side impact was conducted – first for vehicles. In a subsequent impact analysis, the effects of changes (thickness distribution, residual stress, plastic deformation, etc.) during steel forming were examined.