**7. Conclusions**

The first part of the paper presents the IRI indicator, combining the assessment of road surface unevenness with driving speed. This indicator was used to assess unevenness overcoming during the road tests. The movement of the wheel axis during single road unevenness overcoming was described. In the further part of the paper, the road unevenness was used as enforcement during the simulation of the dynamics of the rear suspension system. The paper presents a computational model of the rear suspension system for dynamics analysis. This model enables stress analysis of the suspension beam during obstacle overcoming for two variants: with motors built into wheel hubs and without motors. The finite element method implemented in the ANSYS commercial package was used to model the flexibility of the beam of the semi-dependent rear suspension. Thanks to the use of the MSC.Adams-ANSYS program interface, it was possible to analyze the beam strength for loads acting during unevenness overcoming and to take into account the couplings occurring between the deformable beam and other suspension elements. The results of the numerical simulations allow to formulate the following conclusions:


**Author Contributions:** Conceptualization, P.D., B.B., K.P., H.W., A.U., K.A.; methodology, K.P., H.W.; software, A.U., K.A.; validation, K.A., A.U.; formal analysis K.P., H.W., A.U., K.A.; investigation, P.D., B.B., K.P., H.W., A.U., K.A.; resources, P.D., B.B., K.P., H.W.; data curation, B.B.; writing—original draft preparation, K.P., H.W., A.U., K.A.; writing—review and editing, K.P., H.W., A.U., K.A.; visualization, K.A.; supervision, P.D.; project administration, P.D. All authors have read and agreed to the published version of the manuscript.

**Funding:** The research is a continuation of the project: "Innovative Solutions for Direct Drive of Electric Vehicles", financed by National Centre for Research and Development under the LIDER VII program, in accordance with the agreement: LIDER/24/0082/L-7/15/NCBR/2016 (POLAND). The project received the Research Award (main award) 25th Siemens Award Competition for scientists and research teams (Poland).

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** The data presented in this study are available on request from the corresponding author.

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