In the national economic valuation of road accidents which the Swedish Road Administration uses, both the number of seriously and slightly injured persons, known to the police, is adjusted with the same nonresponse factor (expansion factor) of 2.4. This applies regardless of the type of environment (rural or built-up area), road type and accident type/road user category. It therefore appears necessary to examine how reasonable this expansion factor is at present. In the project, a review has been made of how the reporting of road injuries to the police (police-STRADA) and to the hospitals (hospital-STRADA) differ with respect to degree of injury, accident type/road user category and type of environment. This was done with the help of accident data for 2003-2005 in some counties/ municipalities where, in principle, all accident & emergency hospitals were members of STRADA, an information system for data concerning accidents and injuries in the road transport sector. The study comprises a total of 55,578 injury accidents (including "pedestrian-single"), reported by the police and/or an emergency hospital. If pedestrian-single accidents are excluded, there remain 46,444 injury accidents. Of these, 11,399 (24.5%) were reported only to the police and 24,631 (53%) only to a hospital, while 10,414 (22.4%) were reported to both.