The car's stability can be defined as the safe interaction between the driver and the surrounding conditions, occurring when people or loads are transported from one place to another. Loss of stability may occur for the following reasons: violation of the static stability criteria, when the car overturning or throwing over is determined by its position in space, and not by the forces of inertia, and violation of the dynamic stability criteria, when the car overturned or thrown as a result of inertia forces, dependent on the speed of its movement and arising on a bend, when hitting a stationary obstacle and when driving off the road.
At the moment of the car crash, due to deformation of the bodywork (fenders) or due to other reasons, the car's wheels lock up. Under the action of the forces of inertia and the force of friction, formed at the point of contact of the blocked wheel with the road, the car leaves its straight track. The value of this deviation basically depends on it: which wheel has been blocked, what was the speed of the car at the time of blocking (strokes), on the condition of the road surface and on the type of car. If the right front wheel is blocked (Lynx. 5.34), then the car will swing right- from the direction of rectilinear motion. The distance S from the center of the car to the braked wheel will increase as the car moves, ie the resulting turning moment Pu • S will contribute to the loss of vehicle stability.
The situation becomes the same if the left rear wheel is blocked, but the car will go left (Lynx. 5.35). Distance S., and therefore also the moment of inertia, will decrease as the car moves. The lock of the right rear wheel accompanies the vehicle descending to the right.
Accepting the possibility of blocking any wheel requires a very significant prior calculation, namely: what width of the road must be disposed of, that the car with the appropriate speed does not fall outside its limits, or at what speed the car should go, so that in the event of an accident, road remained on the road.