This thesis is analyzing the basic physical principles based on which it is possible to describe a vehicle hitting a pedestrian. In addition to the theoretical study of collisions there is an analysis of an imaginary collision that happens in everyday life. There is a description of the kinematics of movement of the vehicle and the pedestrian, the method of determining the speed of the vehicle at the beginning of braking, at the moment of impact with the pedestrian and after hitting the pedestrian. In order to determine the causes and circumstances which lead to accidents it is often needed to perform a car expertise (technical analysis) in order for the court to assess the responsibility of individual participants in the accident. For the analysis of traffic accidents, in addition to conventional methods, today there are software programs that are becoming increasingly desirable, and often a necessary tool for work. Programs for the simulation of traffic accidents, as opposed to analytical methods, take into account almost all relevant kinematics parameters in vehicle impact on pedestrians. The purpose of the thesis is to explore the physical basis of the movement of participants in the collision, the method of collecting data on the braking skid marks, deformation of the vehicle, discarded and broken parts, and the method of taking statements from eyewitnesses in order for to obtain an objective and comprehensive understanding of the temporal and spatial course of the accident, and how and where it happened.