A method of assembling a plurality of body structures for forming a vehicle assembly comprising the body structures, the method comprising the steps of: providing a plurality of body structures to be assembled, at least one of the body structures having a deformation region; acquiring information indicating a vehicle assembly type to be formed; mating at least one body structure with another body structure to form the vehicle assembly; and performing a deformation region treatment on at least one deformation region of at least one body structure of the vehicle assembly to form at least one deformable region based on the information indicating vehicle assembly type.