It is especially in the last decade that traffic calming measures (all kind of devices, applications etc.) are also more and more frequent in Slovenia. The Slovenian act about traffic safety defines measures and devices for traffic calming. According to our law the traffic calming devices are physical, light or other devices and obstructions that physically prevent the participants in road traffic to drive with inappropriate speed or they warn them to limit the speed on dangerous road sections. Physical obstructions in Slovenia could (only) be set down on regional national roads and community roads in the settlement/city. Usage of physical traffic calming devices is obligatory near schools, kindergartens and other objects, along which the speed is limited (due to traffic safety for all participants). In the article I presented the results of research that was done in Slovenia. I analyzed different kinds of traffic calming measures (physical devices) from the speed reduction point of view. At the end I also showed the correlation with other research results from abroad.