During a collision of two vehicles, the kinetic energy as function of vehicle velocity and vehicle mass must be converted into energy absorption work of the energy absorbing zones. In order to keep resulting stress on the vehicle occupants to a minimum, the deformation structures within a definite mass range should be compatibly matched to one another.

It will be shown, using a relatively simple crash model which can represenat front-front collision, how the deformation structures of vehicles with differing masses should be designed in order to guarantee a high degree of compatibility, It can be concluded from accident statistics that vehicles should be compatible up to a mass relationship of approx. 1.6:​1. On the basis of three vehicles with differing masses which together are representative of the range of vehicles under study, it is possible to approximately simulate the course of an accident using five vehicle-vehicle collisions.

With the help of an optimization procedure derived from the biological theory of evolution, optimal deformation characteristic curves for head-on collisions are first determined. In this, secondary conditions are also assumed which take the requirements of a front-side collision into account. The result of these calculations is a set of characteristic curves for power level and deformation distance as a function of mass, assuming certain basic conditions.

The German Ministry of Research and Technology has sponsored the project "Development of Compatible Vehicles" which is carried out by the HUK Association, the Technical University of Berlin, and the Volkswagenwerk. This study is part of the above project.