A trial linkage of the road accident and vehicle registration files

Vehicle characteristics are of importance in all phases of road accident. None, however, are recorded by the police on the road accident registration form in The Netherlands. By linking the Vehicle Registration file to the Road Accident file a number of important vehicle characteristics can be added to the accident record. Theoretically it had to be possible to link both files because there was a common key variable viz. the vehicle registration number, which in The Netherlands is unique and stays with the vehicle its whole life. The test linkage was aimed at determining whether it was also practically possible. It was furthermore aimed at determining the completeness and reliability of both files. The fatal accidents of 1981 were selected to serve for the test because only fatal accidents are completely recorded, and 1981 was the most recent available year at the time. These limitations made it possible for SWOV to carry out a manual control on vehicle make and model, as this is often recorded by the police. Based on the conformity found, the validity of the linking by vehicle registration number was found to be 94% and the reliability at least 95%. The conclusion is therefore that the linkage can be accomplished in practice and that it reliably adds useful vehicle characteristics to the police records on fatal road accidents. This complementary information is in the first place important for deeper analysis of the relationship between, on the one hand, accident and injury characteristics and, on the other hand, the vehicle characteristics.