We are living an ecological decade. The interactions between man/machine/environment are emphasized and an equilibrium is always looked for in such way this three protagonists are worked with ordination and discipline to ensure their interfaces be effected without traumatism. The aspects concerning comfort and safety do not survive isolated. Nowadays, when they are considered, they possess strong interactions although they can be treated separately. Traffic accident analysis are without doubt, the main source to furnish informations for the development of automotive vehicles concerning safety.We are making a pioneer work in Brazil (probably in the South Hemisphere). We try to report our experiences concerning traffic accident analysis we have obtained with commercial vehicles (buses and trucks) in a period of two years, as well as the details and discussions regarding the main conclusions.