The Swiss federal road accident statistics are based on accidents reported by police authorities. It comprises accidents that result in injury or death on public roads and places, involving at least one vehicle. Every accident recorded by the police has to be reported to the federal office of statistics. Although every accident with 'damage to persons' has to be reported to the police by law, for different reasons not all of them are reported. In fact, there is a substantial underreporting of road traffic casualties. In addition the statistics might be biased by the fact that the injury severities are estimated by policemen and not by professionals. Additional source of bias might be the fact that a certain part of the fatal road accidents are actually not accidents but suicides.
In order that in the future preferably all accidents with injured persons can be registered without the mentioned biases, the police reported accident data should be complemented by medical data of hospitals, medical practitioners and accident insurence agencies.
The resulting complemented and corrected accident data base would then allow the planning of more effective prevention measures. As the data base would be updated yearly, it could also be used for checking the performance of realised measures.
The aim of the research project is the completion of police reported accident data with medical data of hospitals and medical practitioners.
The completion of data should enable
- a more precise estimation of the number of unreported casualties;
- a more precise estimation of road accident injury severities (adjustment of existing bias);
- an estimation of the percentage of suicides.
These improvements allow for the planning of more effective prevention measures. Additionally the resulting data should allow a more precise estimation of the social costs of accidents.
The pilot scheme is carried out in the city of Zürich. The aim is to establish the basic knowledge which would make possible to adopt such a system in other cities, cantons and at federal level if necessary.
The following steps took place:
Literature review on traffic accident analysis using hospital data.
Analysis of Medical Statistics of Hospitals (BFS) and assessment of the adequacy of the data features contained for the purpose of research. Creation of the Catalog on gaps and missing data.
Analysis of the suitability of the central statistics of accident insurance (UVG statistics) for the research and comparison of characteristic values with the corresponding characteristic of medical statistics of the hospitals.
Investigations in Zurich hospitals / investigations at private general practitioners in the city of Zurich.
Analysis of possibilities and selection of the most appropriate method for the data link.
The project outputs are the following:
- Implementation of the selected method and extrapolation
- Statistical analysis with the optimized traffic accident statistics
- Conclusions, recommendations and reporting
The research has a strong implication for reporting on accident insurance and for better planning of measures to decrease the traffic accidents and their impacts.