The road traffic safety in Slovenia was improved in recent years mainly due tothe construction of new motorway sections and their increased use as a result of the introduction of vignettes. Stricter sanctions for offenders alsoimproved the road safety.The effect of stricter sanctions is usually short-lived and requires periodic tightening, which in our opinion is not reasonable any more. Therefore it is necessary to look for other options to achieve goalsin the National road safety program - road traffic accidents effects reduction (number of killed and seriously injured). We estimate that the opportunity is in improvementof the secondary road network. Our hypothesisis that it is possible to significantly improve the level of trafficsafety with investments in new bypasses, modernization, reconstruction and resurfacing of roads. This paper presents the results of analysis of investment in road infrastructure impact ona road safety.