The role of a traffic safety expert is to study and analyze the causes and forms of manifestations of traffic accidents. Based on the knowledge acquired, the appropriate countermeasures and preventive measures are designed, which will influence the decrease of number of traffic accidents and their consequences. Traffic engineers and traffic safety experts should estimate the state of road traffic safety, to define black spots and form a high-quality base of usable data. Development projects should base on before-after studies, which make the foundation to reach quality conclusions on legality of traffic accident occurrence. This knowledge offers the possibility to determine and develop the appropriate models for prediction of traffic accidents. The development of prognostic models has shown to be a very useful method in the study of traffic accidents and the increase of traffic safety level.