The stresses arising in a vehicle structural part during the operation period could be divided into three essential components. The extreme values of these components and their distribution function may be derived. Using appropriate crack propagation functions one can define the momentary service strength of the structure and the damage-function. On the basis of the new fracture model presented, the life distribution can be interpreted unambiguously. By using certain assumptions, the deverage value and the scatter of the life can be derived. The new fracture model allows the several fracture types, like static, pure dynamic, pure fatigue, and general fractures to be treated on the same basis.