In the Netherlands, SWOV annually assesses the number of serious road injuries based on two sources:
- Database of registered road crashes in the Netherlands (BRON).
In BRON, the Ministry of Infrastructure and Water Management collects and publishes road crash data based on police registration, notifications by road inspectors of the Dutch national road authority and information from media reports. This database contains information on crash characteristics such as road design features, vehicle characteristics and casualty information. BRON does not contain reliable information about injury severity, and a lot of casualties are missing, particularly those resulting from crashes not involving a motor vehicle.
- The national hospital discharge register (LBZ)
LBZ is a database maintained by Dutch Hospital Data (DHD). It contains injury data of patients discharged after hospitalisation. Examples of data that are registered are crash type, injured body parts and injury types. LBZ contains little information about the crash itself; for example, the crash location is not recorded in LBZ. We assume that LBZ contains all road casualties admitted to hospital. Yet, in the database, not all casualties are identifiable as road casualties. Approximately 95% of serious road injuries can be found in LBZ [1].
SWOV estimates the number of serious road injuries in the Netherlands by linking and analysing the data from both data sources, and also estimates how many serious road injuries are missing in both databases or cannot be recognised as such [1].
The quality of both data sources is crucial for a reliable estimate of the number of serious road injuries. Since the year 2010, the quality of, most notably, BRON has greatly decreased [11]: still sufficient to determine the total number of serious road injuries and motor vehicle involvement, but insufficient to make reliable statements about the trends in serious road injuries with certain characteristics (such as types of road users, age groups, etc.) [1]. About 12% of serious road injuries from crashes without motor vehicles (e.g. cyclists crashing with a bollard or another cyclist) are found in BRON; and about 65% of serious road injuries from crashes with motor vehicles [1]. Based on hospital discharge register LBZ, a more reliable indication can be given of a number of characteristics of serious road injuries. Because LBZ does not contain information about crash location, it is not possible to distinguish between different types of locations on the basis of LBZ. It is hoped that in the future ambulance data can add more information about crash locations.
