The paper is developed following a scientific research, developed in the Department of Road construction and Transport Facilities at UACEG and successfully defended in October 2018. The problem of the economic impact of road accidents on the economies of the countries and in particular the Republic of Bulgaria is examined in detail. A detailed analysis of the situation in Bulgaria has been made, the system’s positive and negative effects have been taken into account and a detailed model for calculating external costs due to road accidents of all time periods has been developed. The model can be used to calculate costs both globally – for the whole country as well as for a regional or a specific road or road section. Costs can also be calculated by other criteria, such as BGN (EUR) / vkm; BGN (EUR) / death ( or injured ); BGN (EUR) / accident and so on. At the end, the external costs of road accidents in the Republic of Bulgaria for 2017 are calculated. To achieve the objectives set at the beginning, a thorough analysis of the entire system related to road accidents, including the prosecutor’s office, the police, the healthcare, the insurance business. To determine indirect costs, the largest sociological survey on the attitude of Bulgarian society towards road accidents was developed and conducted.