Serious road injuries 2015 : Estimate of the number of serious road injuries in 2015. The number of serious road injuries (SRI) in 2015 has been estimated at 21 300. This is 600 higher (+3%) than the estimate of the number of SRI in 2014. The number of serious road injuries is an important road safety indicator. Since 2010, a serious road injury is defined as follows in the Netherlands: A serious road injury is a road crash casualty who has been admitted to hospital with a minimum injury severity of 2, expressed in MAIS (Maximum Abbreviated Injury Score5), and who also did not die of the consequences within 30 days after the crash. No register is available in which all serious road injuries are registered. Since 2008, the number of serious road injuries is therefore determined by comparing the data in two different data sources: BRON6 (police registration) and the LBZ7 (hospital discharge data). All serious traffic injuries are assumed to occur in the LBZ. The method to determine the number of serious road injuries consists of three steps: 1. linking BRON and LBZ; 2. a correction for incompleteness of the LBZ and for crashes that did not occur on a public road; 3. a correction for misclassifications in the LBZ. Not all road crash casualties can be identified in the LBZ, because sometimes a wrong external cause is encoded. Compared to 2014, the number of SRI in 2015 increased with 3% to approximately 21 300. This increase occurred both in the relatively lighter injury severity category MAIS2 (+ 2%) and in the relatively heavier injury severity category MAIS3+ (+ 4%). Like in the preceding year, it is also not possible in 2015 to make a distribution of the total number of serious road injuries by mode of transport. This is due to the fact that for a large number of casualties (41%) the mode of transport has not been registered in BRON. Moreover, in 2015 this is often also the case for the crash opponent of the casualty. This is an undesirable development: it limits the insight in road safety problems. We can, however, give insight in the developments of individual groups of casualties. For this, we use the patients who are registered in the LBZ with serious traffic injury (MAIS2+). In the year 2015, 20,411 patients in this category were discharged from hospital. It is uncertain whether the unobserved casualties (around 1,000) are represented correctly. This uncertainty means that in further distributions the data should be interpreted with caution. If we nevertheless rely on the development of the numbers registered in LBZ, the increase seems to occur for all categories (both for crashes with motor vehicles and for crashes without motor vehicles). This is expressed by a constant proportion of crashes involving motor vehicles (approximately 47%) and crashes not involving motor vehicles (approximately 53%). In the Road Safety Monitor SWOV carries out detailed analyses to interpret these and other developments. The results will be described in the monitor report of Korving et al. (2016), which will be published simultaneously. Until the year 2010 the estimate of the number of SRI also contained data about the distribution by the category of severity, region and mode of transport. Since 2010, however, the estimate has become less accurate for three reasons: • the transition by hospitals to a different encoding system (from ICD9-CM to ICD108); • a decline in the registration of casualties in BRON; • a less complete LBZ file. The method used to estimate the number of serious road injuries in 2015 is largely the same as last year. The most practical difference is that the selection from the LBZ database could not be handed over to SWOV directly, due to privacy legislation. For this reason the data were provided to Statistics Netherlands this time, and nearly all of the SWOV research was carried out in the secure on-site environment of Statistics Netherlands (CBS). A solution also had to be found for the missing information in BRON about the modes of transport of both casualty and crash opponent. Due to the reduced accuracy of the estimation since 2009, there is only limited stratification for severity category (MAIS2 and MAIS3+) and mode of transport (motor vehicle crashes and non-motor vehicle crashes). This is done retrospectively and it is therefore possible to produce a consistent series. However, stratifications for other variables are unfortunately no longer possible. For the third year in a row, the introduction of the registration system KenmerkenmeldingPLUS at the police force (in 2013), has led to an increase in the number of correct matches between BRON records and LBZ records. Nevertheless, the quality of the matches is still insufficient. Certain fields are missing in BRON (hospital name, transport modes and other characteristics), while these are necessary for a correct link and for calculating the number of serious road injuries. Thereby, it is still not possible to make more distributions in the number of serious traffic injuries. This requires further improvement of the quality of the registration, and especially of the quality the input. In recent years, the LBZ has become more and more complete. In 2015 less than 1% of clinical admissions are missing. The new coding instruction in hospitals, with regard to the registration of external causes (DHD ICD10 coding advice (2015)), seems to work well in most hospitals. In 2015, casualties among motorcycle riders are registered separately again. Also it is now possible to distinguish between moped and light moped, and between racing bike and pedelec (as far as information is present in the medical record). Another initiative to gain more insight in road safety problems is making data from ambulance rides available for road safety research. In 2013, this initiative was started by the Ministry of Infrastructure and the Environment, in collaboration with RIVM (National Institute for Public Health), Rijkswaterstaat Water, Traffic and Living environment (WVL) and SWOV. In the autumn of 2015 this has led to a database of anonymised crash and patient data of emergency ambulance rides in the period 2009-2012. Because this database does not yet contain data of years after 2012, we cannot yet use this database for additional analyses.
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