A vehicle door is designed to collapse in the longitudinal direction of the vehicle in such a way that in the case of a maximum longitudinal force slightly below that of the most serious accident, longitudinal deformation occurs and the axial supporting force of the vehicle door simultaneously remains as high as possible. To produce this longitudinal deformability, crimps running parallel in the vertical direction are provided in the structural members of the door and in a door well reinforcement.
A bar construction comprising a generally trapezoidal and open cross-sectional configuration which includes a center-flange (6), two webs (7) which embrace the center-flange, and side-flanges (8) which extend outwardly from a respective side of the bar and connect with respective web (7). The bar may optionally include a first section (1) of constant cross-section in the center part of the bar. The bar includes at least one second section (2) which has a center-flange (6) whose width (b) decrease towards one end (5) of the bar. A transition part (3,4) of generally trapezoidal configuration is provided between the second section (2) and the end (5) of the bar. The second section (2) has side-flanges (8) whose widths (c) decrease towards one end of the bar. The second section (2) has a generally constant height (h).
