The issues of road traffic safety in the Republic of Croatia with reference to speed as a cause and an element in the occurrence of traffic accidents is presented in the thesis. The number of deaths in Croatia was growing uncontrollably until the Republic of Croatia actively started implementing the National Road Traffic Safety Programme, that is, until the Government of the Republic of Croatia passed the new Road Traffic Safety Act. The new Act was passed in 2008 and it provided significantly higher fines for offenders than the previous acts. The year 2008 may be taken as the beginning of systematic and planned work on increasing road traffic safety, which resulted in a considerably smaller number of traffic accidents and casualties. According to statistics, the largest problem for road traffic safety is improper and unadjusted speed as the cause of the highest number of traffic accidents and deaths. Systematic and joint action of all entities responsible for road traffic safety is required to eliminate the negative consequences or at least reduce them to a minimum. A traffic accident is a tragic event that should be thoroughly analysed, that is, a quality investigation should be conducted and all the required information should be collected, because a well conducted investigation can lead to certain conclusions that can be used to further focus the efforts and resources to increase road traffic safety. By monitoring the number of traffic accidents on the basis of the place where they occur, it is possible to determine the “black spots” on roads where traffic accidents occur in greater numbers and increase speed control with the aim of reducing speed and calming the traffic.