**Piotr Aleksandrowicz**

Department of Machine Operation and Transport, University of Science and Technology in Bydgoszcz, 85-796 Bydgoszcz, Poland; p.aleksandrowicz@utp.edu.pl

Received: 21 August 2020; Accepted: 4 September 2020; Published: 7 September 2020

**Abstract:** The analyses performed by the experts are crucial for the settlement of court disputes, and they have legal consequences for the parties to legal proceedings. The reliability of the simulation result is crucial. First, in article, an impact simulation was performed with the use of the program default data. Next, the impact parameters were identified from a crash test, and a simulation was presented. Due to the di fficulties in obtaining the data identified, the experts usually take advantage of simplifications using only default data provided by the simulation program. This article includes the original conclusions on specific reasons of simplified collision modeling in Multi Body Systems (MBS) programs and provides specific directions of development of the V-SIM4 program used in the study to enhance the models applied. This manuscript indicates a direction for crash model development in MBS programs to consider a varied 3D body space zones sti ffness related to the structure of the car body and the internal car elements instead of modeling the car body as a solid with an average sti ffness. Such an approach would provide an alternative to Finite Element Method (FEM) convention modeling.

**Keywords:** collision modeling; mechanical parameters; contact detection
