Safe speed of a passenger car in circular motion

In this paper, selected elements of the theory of the car's motion were presented. It was emphasised that it is extremely important to know the rules of behaviour of a car in curvilinear motion, an example of which is a curve, especially when driving in adverse weather conditions resulting in the significant reduction of the car's traction to the surface. The active electronic stability programme (ESP) of the car's trajectory, its principle of operation and benefits of use were briefly discussed. The next part was to present the basics of the mechanics of a vehicle's motion, especially the forces acting on a car during its stop phase, the forces acting on the curve of the road. On this basis, the basic equilibrium equations were presented, which in turn led to defining the correlation for determining the so-called safe speed of driving in circular motion, which also guarantees the impossibility of the cars skidding. In the further part, the calculations, in accordance with the BMW 320d car's data were made. Hypothetically, it was assumed that this car might have only a front-wheel drive, only a rear-wheel drive or a four-wheel drive. The idea was to check to what extent the type of drive has an impact on the achieved value of the safe speed of driving in the circular motion with a minimum turning radius for this vehicle. The article was completed with short conclusions, in which the importance of the electronic stability programme (ESP) of the car's trajectory was emphasised.