Transport and communications are an important industry area which facilitates the development of other industries. Transport industry makes up about 7% of the European gros domestic product and about 5% of all jobs. However, notwithstanding its positive influence of the nation's economic welfare, the automobilization causes also such negative phenomena as the air pollution, noise, traffic jams and road traffic accidents (RTA). During the recent years, the number of the registered RTAs has increased. During four years it had grown by more than 25%. The greatest increase was in the period from 2006 till 2007, when the number of RTAs grew by 17%. In 2006, RTAs caused economic damages in the amount of LVL 217,12 million. The aim of this article is to analyze the economic damages, caused by RTAs, identify the factors, influencing road traffic accidents, and analyze the efficiency of the investments into the reconstructed road sections. For better interpretation there is: elaborated a model of interaction between factors which influence road traffic accidents and efforts which should be made to reduce amount of RTAs; there is also made an analyse about the change of RTA in two reconstructed road sections in Latvia. An analyse showed that no road reconstructions with the aim to reduce the number of RTAs are as effective as the change of the traffic participants' behaviour. At the end of the paper are given proposals for minimizing the number of RTAs. Given analysis can be used in future planning of needed investments for reconstructing of motorways and investments for changing human behaviour.