**4. Conclusions**

The impact parameters identification method proposed involves the performance of the procedures: a test selection, a division of the film into single frames, the measurements and photograph scaling, the selection of the reference base for the overlap analysis for the test vehicle and the simulated vehicle, the top and bottom views, and a change in the impact parameters (sti ffness in the compression and restitution phase, the coe fficient of restitution, a change in the plane of contact force, and wheel blocking) for the best image matching. Having received the image overlap from the recorded test and vector styling of the simulated vehicle in time t of the collision, the impact parameters identified must be entered into the simulation of the incident reconstructed. The approach in that convention increases the possibilities of the impact reconstruction by the road accident experts and developing expertise for courts with no access to test impact forces data.

Further studies should, therefore, be performed towards the development of the crash models in MBS programs to facilitate considering a varied sti ffness of the body zones in its 3D space connected with the vehicle body structure and its internal elements and not, as it has been the case so far, of the vehicle body, its solid with the average sti ffness. A solution to this problem would provide an alternative to time-consuming modeling in the FEM convention.

The study shows that the parameters used for simulations in practice should be selected based on the actual accidents which have been filmed and on crash tests. The study results have demonstrated that, for the V-SIM default parameters, an accurate reconstruction of the course of the impact was not possible due to:


The expert witnesses applying programs for expertise development should consider the above modeling simplifications not to assume an inadequate simulation result as it has a negative e ffect for insurance companies and court decisions.

The study results also demonstrate that the vehicle impact model in V-SIM should be further developed to:


To recapitulate, this research developed a methodology of identifying the crash parameters to be applied for various vehicles and various crash velocities, as well as various kinds of barriers and crashes. Thus, it is possible to provide the adequate, compliant with the real-life course of the crash, result of the simulation using the MBS programs, although, they currently use more simple models of the detection of collision and crash, as compared with the FEM programs. However, by o ffering a much shorter time of calculations and a high number of numerical vehicle models in their databases, they provide an interesting and developmental alternative for the FEM programs. The research performed also facilitated determining a further development of models in the MBS programs which should focus on developing the crash models to consider a varied sti ffness of the body zones in its 3D space. Next to the development of the aspects of crash modeling presented in the article, the e ffects for practical applications have also been provided for the experts performing vehicle crash simulations, as well as the guidelines for optimizing the functionality and the calculations precision of the V-SIM program, in the future to be used by designers when working on the successive versions of that IT tool.

**Funding:** This research received no external funding.

**Conflicts of Interest:** The authors declare no conflict of interest.
