摘要:The evolution of modal split of freight transport is causing the heterogenization of traffic flows on motorways, so the aim of the paper is to explore the effects of changing structure of traffic flows on Slovenian motorways on road safety and to assess this effect in a financial way. We have calculated crash costs of accidents that were caused by trucks as well as the crash costs of the accidents involving trucks. In addition, we created two safety perfor-mance functions for prediction of the number of traffic accidents on Slovenian motor-ways. The number and the share of accidents involving trucks on Slovenian motorways is increasing as well as the amount of traffic work done by the trucks is, so it is possible to expect increasing crash costs of such accidents on Slovenian motorways. DOI: 10.15458/85451.22