Road safety performance indicators (RSPI) are policy tools which describe the extent of insecure operational safety conditions within traffic systems. This study describes the production of an RSPI which represents the presence within a country's vehicle fleet, of vehicles that may not effectively protect an occupant in a collision. This work is highly original, as it uses the entire vehicle database of European Union Member States in order to estimate the average level of passive safety offered by the entire fleet in each country. The EuroNCAP safety ratings and vehicle age of each vehicle in each fleet have been obtained to calculate the RSPI. The methodology used could be adopted as an international standard.