Many studies have been performed in the field of compatibility between cars. Two test procedures with assessment have been developed to evaluate the compatibility level. The FWDB test is conducted at 56km/h against a 100% overlap rigid wall with deformable elements. The PDB test is a 50% overlap test at 60km/h against a Progressive Deformable Barrier. Assessment criteria are based on the force for FWDB test and on the deformation of the barrier for the PDB test.

If new assessment criteria are often proposed, few outcomes are provided concerning test procedures themselves, even though a lot of open issues still exist.

The aim of this paper is not to review all of them, but to conduct a methodological and physical analysis of both candidate test procedures. “Physical analysis” because it is based on the three incompatibility physical phenomena responsible for real car incompatibility (geometry, energy and stiffness mismatching). And “methodological” because both test procedures are studied using physical tests and virtual testing. Assessment criteria are therefore not considered.

Moreover, as a general agreement exists today that multiple load path with connections could help car front-ends to interact, PSA will present component tests and virtual testing with or without lower load path. Significant outcomes are provided concerning the efficiency of the technical procedures:​

1. Both procedures can detect a geometry change such as the absence of load path.
2. Both procedures can measure a global force. However, its interpretation for the FWDB test is difficult due to the very limited deformation of the front-end undergone in this test.
3. Only the PDB test is able to draw up an energy absorption statement which is the only way to evaluate the car crash severity. For the FWDB test, this point represents a major difficulty because energy absorption by deformable elements is significant, about 50kJ.