## 2 Operational Conditions and Examples of Suspension System Damage  
The suspension system is one of the vehicle systems most vulnerable to damage and even premature wear. This stems from operational conditions during use. A summary of factors conducive to the destruction of vehicle suspension system components is presented in Figure 1.  
One of the factors acting on the vehicle's suspension system is static loads, the value of which does not depend on the vehicle's movement. These loads include the forces  
Figure 1: Factors conducive to the destruction of vehicle suspension system components. from the vehicle's total weight and substrate reactions passing through the contact points between the wheels and the roadway. Those loads are transferred directly to the suspension system and, in combination with other factors, in particular dynamic ones, may lead to the initiation of damage. In the following sections of this article, it will be possible to trace that relationship and see how it affects the change in the deflection of suspension system components. Another factor influencing the condition of the suspension system components is dynamic phenomena, which mainly depend on the interaction of the wheel with the road pavement and driving along roads with sloping pavement. Those loads usually manifest themselves as vibrations, which may be dangerous for vehicle users and affect the life of the suspension system. On the road, longitudinal and transverse roughness such as potholes, depressions (Figure 2), waves, or corrugations pose a serious threat to road users and the suspension system itself. Additional elements installed on the roadway that may affect the technical condition of the suspension system are road bumps and raised pedestrian crossings. On the one hand, these elements improve road safety but, on the other, regular driving over these obstacles at inappropriate speeds will, over time, influence the deterioration of the technical condition of the suspension system components. Regular driving on a deformed road pavement may result in the unexpected wear of the suspension system components and in sudden vehicle path changes. An example of such a situation with sample consequences is discussed in item 4.3. It must therefore be concluded that the standard of the road on which the vehicle is driven has the greatest influence on the safety and condition of the suspension system components. As indicated by the results of investigations conducted by various authors, the deterioration of the road standard results in a nearly twofold increase in the discomfort index and safety factor and a threefold increase in the range of suspension system deflection. An increase in those parameters enhances the possibility of fatigue wear on suspension components. When pointing out the factors that affect the life of the suspension system, it is necessary to mention impurities on the road, which include small stones, road salt, or other chemical compounds that reduce roadway slipperiness [21]. At this point, it should be mentioned that water may be present on the roadway after precipitation. Water penetrating into the suspension system may accelerate the degradation of the various components [22]. Figure 2: Examples of damaged road pavement. In addition to asphalt roads, gravel roads are also available for motor traffic. Regular driving on such roads causes loose gravel, dust, and sand to enter the space between suspension system components. Moving in the space between the components under the influence of oscillatory tangential displacements, those products initiate the development of abrasive wear. Driving skills also influence the technical condition of the suspension system [23]. Speed selection and the skills related to overcoming obstacles etc. have a significant influence on the operation of the suspension system. The vehicle driver should react to changing road conditions, ruts, or cavities in the pavement early enough.