## 5 Conclusions  
On the basis of the conducted tests, the following conclusions can be drawn regarding tire damage on a truck tractor:  
1. There were no indications that the tire rupture was caused by external exposure to the metal part. Figure 16: Profile deformation under a load of (**a**) 603 kg; (**b**) 676 kg. 2. Crack analysis (e.g., delamination of material coatings and traces of corrosion on steel wires) shows that the structure of the tire was weakened in the place of the crack. This could be the result of two independent reasons. The first of them could have been caused by much earlier damage to the tire, followed by the ingress of moisture inside, which initiated the corrosion processes of the steel cord wires. The second reason may be related to the tire's design defect in the use of a cord with traces of corrosion during production. 3. As indicated in the literature, in cases where the structure of the tire is weakened, it may become unsealed (cracked) during the operation of the vehicle. Taking into account the authors' experience, there has not been a case of tire fracture in a situation where the place of weakening of its structure did not coincide with the place of external force. However, such a possibility cannot be categorically ruled out. 4. Disclosed traces of abrasions on the tire sidewall, on both sides (on the \"belt\"), are a significant premise for accepting with a very high probability that before the collision with Car A, the left front wheel of the truck tractor made at least one full turn during which the tire vibrated, indicating a leakage occurred prior to the crash. There is a very high probability of material evidence that the leakage of the left front tire on the truck tractor took place before the collision with Car A. In situations where the tires of trucks mounted on the axle of the steered wheels become unsealed, the vehicle's trajectory changes, which at the initial stage are not able to be controlled by the drivers. There are known cases where such incidents did not produce physical effects. Occasionally, if sufficient space was available, drivers were able to regain control of the vehicle and keep it safely within the road. In most cases, however, the leakage phenomenon is so dynamic, sudden and surprising for the driver that it results in the destruction of the vehicle and/or a collision with other vehicles on its uncontrolled path. In the analyzed case, it can be stated that the road section in question was not wide enough to regain control of the articulated vehicle and avoid a collision with oncoming vehicles. The utilitarian conclusion from work is that it is suggested to withdraw tires with cracks on the side surface from service. Progressive degradation of this surface may cause penetration of moisture and aggressive agents (road maintenance agents in winter) and cause corrosion of steel wires. In addition, testing of wire samples from each series of deliveries should be introduced in production plants. This would eliminate the material with initiated corrosion directed to the production line. This procedure would increase production costs, but it would clearly increase the quality of the product and the safety of operation in road traffic. Conceptualization, K.D., S.T. and J.C.; methodology, K.D., S.T., J.C. and A.N. ; software, K.D. and S.T. ; validation, J.C., J.V. and Z.K. ; formal analysis, K.D., S.T. and A.N. ; investigation, K.D., S.T. and J.C.; resources, S.T., J.C. and A.N. ; data curation, S.T. ; writing--original draft preparation, K.D., S.T., J.C., A.N., J.V. and Z.K. ; writing--review and editing, K.D., S.T., J.C., A.N. and J.V. ; visualization, J.C., J.V. and Z.K. ; supervision, A.N. and J.V; project administration, J.C. and A.N. ; funding acquisition, K.D., S.T., J.C. and J.V. All authors have read and agreed to the published version of the manuscript. The project was financed in the framework of the project Lublin University of Technology-Regional Excellence Initiative, funded by the Polish Ministry of Science and Higher Education (contract no.