## 3 Characterization of Damaged Tire and Methods of its Testing  
According to the specification found on the tested tire, it was identified as follows:  
* Primewell PTL711 tire;
* Size: 385/65R22.5 160K (160-load index: 4500 kg; K-speed index: 110 km/h);
* 18 PR-conventional number of canvases (interleaves);
* A radial, tubeless, all-steel cord tire designed for long-distance transport;
* According to the additional load capacity marking on the sidewall, the maximum load is 4500 kg at a pressure of 900 kPa;
* The tire has European approval (E4 0019845 010950-3) and the American safety certificate DOT 9U3W J92;
* The tire is adapted to regeneration by deepening the tread (\"regroovable\" designation). During the inspection of the damaged tire, chalk markings were applied to its side surface (Figure 4), by means of which the circumference was divided into fragments, marking them using the approximate values of the angular degrees: 0\({}^{\circ}\), 90\({}^{\circ}\), 270\({}^{\circ}\), 360\({}^{\circ}\). Additionally, the direction of rotation of the tire while driving is marked with an arrow. The applied signs mean the Z-outer side and the W-inner side. The terms inside and outside of a tire correspond to the way it is mounted on the rim and positioned in relation to the direction of movement of the truck tractor. Upon visual inspection of the tire sidewall from the \"inside\" side, the following marks and damages were identified:  
* A crack on the side of the tire, approximately 300 mm long (marked with number 4 in Figure 5), located along the angular length of 270 \(\div\) 315\({}^{\circ}\) W on the part of the tire named \"belt\";
* Irregular sidewall abrasions on the \"belt\" on both sides of the tire around the entire circumference;
* Scratches on the side of the tire close to the bead (marked with numbers 5 and 6 in Figures 5 and 6) at the angular length of 70 \(\div\) 180\({}^{\circ}\) W;
* Local deformation of the side resulted from damage to the cord (Figure 7), which was at the 110\({}^{\circ}\) W site. * Inspection of the tire tread allowed us to identify the following characteristics:
* Local loss of material on the tread face with the exposed cord (marked with the number 1 in Figure 8), which was in the place marked with 90\({}^{\circ}\) Z;
* Tearing of the tread face (marked with number 2 in Figure 9), located in the place marked 140\({}^{\circ}\) W;
* The structure of the material in the grooves and edges of the tread indicates that the tire tread has not been regrooved. Figure 4: Tire markings applied during the tests: (**a**) inner side of the tire; (**b**) outer side. Figure 5: View of the inside of the tire of the left front wheel of a truck tractor. Figure 6: Scratches on the inner side of the tire (near the bead). Figure 7: Local deformation of the sidewall on the inner side (indicated by an arrow). Damage in the form of deformed edges was found on both sides of the wheel rim, while the extent of deformation on the outer side was greater than on the inner side. The deformation of the rim on the outer side was (during the post-accident inspection) on the side opposite to the crack in the tire sidewall; Figure 10.  
Relating the location of the damage to the wheel rim on its outer side to the damage to the tire, it was found that the local material loss on the tread face (Figure 8) was on a plane perpendicular to the side of the wheel and passing through the place of maximum deformation of the rim edge. The deformation of the wheel rim on its outer side can be explained as a result of a collision with Car A with which the wheel first came into contact or as a result of the wheel contacting with deformed parts of the truck's shell, e.g., cab steps, which were deformed and disintegrated as a result of successive impacts to the vehicle. It was assumed that the point of application of the force resulting from an impact is at the point of maximum deformation of the rim.