This work deals with the development of a methodology for reliable analysis of disaggregate data contained in the NTUA database, allowing for extraction of basic comprehensive conclusions for the road accident characteristics in Greece and consequently for the causes of these accidents.  A typology of the basic road accident analysis methodologies is proposed, allowing the road safety researcher to have a complete image of basic advantages, drawbacks and limits of these methodologies through concrete examples.  It was shown that the use of absolute numbers, percentages and time-series should take place with great attention on behalf of the researcher, given that in most cases they do not provide sufficient information for the risk exposure of the road user.  On the contrary, accident and severity rates as well as percentages related to accident type provide the possibility for more comprehensive analysis of the road safety characteristics and the causes of road accidents.