Incidence of road injuries in Slovenia

[Download detailed results tables: Slovenia-WebTables]

Last Updated: Sept 27 2009

Important: Please note that the results presented here are preliminary. Additional adjustments will be necessary as the results are made consistent with the ongoing Global Burden of Disease (GBD-2005) project, for which the results presented here are an input. Final estimates of the GBD-2005 study will be released in late 2010.  

About this report

Reliable statistics of road injuries are an essential input for describing the public health burden of injuries, evaluating the impact of safety policies, and benchmarking achievements. While injury surveillance systems are common in high income countries, most low and middle income countries are unlikely to have such capacity for several decades. In the interim, estimates should be derived by harmonizing injury statistics from the wide array of data sources that may be available in a country or region. 

This report summarizes our findings for the incidence of deaths and non-fatal injuries from road crashes in Slovenia. It is one of a series of national road injury assessments that we are producing during the course of this project. The intended audience of these reports includes the global donor community, the international research community, and national health and transport policy makers. We are committed to keeping this project open-source and collaborative in nature. All readers are encouraged to provide feedback to help improve methods, incorporate other sources of information, and suggest more effective methods for communicating these results.

Summary Results

In 2005, road crashes resulted in 274 deaths in Slovenia representing an annual injury rate of 13.7 deaths per 100,000 people. In addition, almost 56,000 people were victims of non-fatal injuries due to road crashes. While the road injury death rate in Slovenia is typical of other countries in the Europe and Central Asia region (Figure 1), it is 2.3 times the death rate in countries with the best road safety performance (Sweden, UK, and Netherlands). 

Injuries as a whole, including from unintentional and intentional causes, resulted in 1435 deaths or 7.6% of all deaths in Slovenia in 2005. 

Road injuries are the third leading cause of injury deaths in Slovenia, after suicides and falls (Table 1). There are over ten times as many deaths from road injuries in Slovenia as homicides. In 2005, road injuries account for nearly one-fifth of all injury deaths in Slovenia. 

How did we compute these estimates?

Our general methodology for estimating deaths and non-fatal injuries involves piecing together data from a wide array of sources that typically include death registers, hospital records, funeral records, health surveys, and police reports. This requires filling information gaps, mapping from varying case definitions, deriving population based incidence estimates from sources that may not track denominator populations, and appropriately reapportioning cases assigned to poorly specified causes. For a general description of the broad methodology, please visit the Methods-overview section of our website.

The following sections describe the specific data sources used, the estimation methods, and the key results for our estimates of road injuries in Slovenia. The analytical adjustments to the data introduce uncertainty in the estimates. Thus, wherever possible, we have outlined the effects of the adjustments on the estimates. 

Overview of data sources

We estimated the incidence and distribution of road injury deaths in Slovenia using national death registration data obtained from the WHO Mortality Database. We estimated the incidence and distribution of non-fatal injury deaths using the results of the 2002/2003 World Health Surveys.

Estimates of road injury deaths

Our review of data sources for estimating national road injury deaths in Slovenia revealed two potential data systems: national death registration data and police reports. In this study, we have computed estimates of national road injury deaths from the former (death registration) and compared them with those reported by the police. We obtained death registration data from the publicly available WHO Mortality Database. These data are tabulations of deaths recorded by national civil registration systems. Typically these systems record age, sex, and causes of death coded using principles of the International Statistical Classification of Diseases (ICD). A total of 35 years of data were available, most recently for the year 2007. 

Reclassification to GBD-2005 definitions: We reclassified age into 38 age-sex groups. The age definitions match those used by the GBD-2005 project and are available on the GBD-Injury expert group website. Click here to go directly to the age definitions. We reclassified the ICD coded deaths to the definitions of road injuries (and other injuries) as recommended by the GBD-Injury expert group (click here for full details).  These definitions map all ICD codes for external causes of injury to 48 fully-specified cause categories and 21 partially-specified and undetermined cause categories. The fully-specified cause categories include nine road-user categories:

In addition, there are two partially-specified sub-categories of road injuries:

Table 2 shows the distribution of the 1,435 injury deaths reported in the death registration data for the year 2005. It should be noted that the 21 partially-specified categories have a hierarchical structure of specificity and many of these categories are not related with road injuries. 

We assessed the quality of the death registration data based on the distribution of the number of deaths in the partially specified categories and found the quality of the data to be relatively high. As shown in Table 2, 6.1% of the deaths that are specified as being from road injuries do not have a road-user specified. An additional 2.2% of all transport deaths do not have a transport mode specified. Notably, only 0.2% of the injury deaths specified as being from unintentional injuries do not have an injury mechanism specified. Our analysis of global data has found that this category can exceed 20% in many countries.  

Reallocation of injury deaths coded to partially-specified causes: 

The effect of these redistribution steps is evident from Figure 2. The death registration data has 261 deaths specified as road injuries. As expected from the distribution of deaths shown in Table 2, the reallocation of deaths coded to partially specified causes changes the total road death count little. This results in an increase of 13 deaths. 

Adjustments that have not applied yet: Two key adjustments that are likely to modify the road injury death counts have not been applied yet. First, we have not reallocated deaths coded to unspecified causes outside the ICD injury chapter. This reallocation has not been done yet because research into the causes of deaths coded to this category is currently ongoing. However, it should be noted that in Slovenia, only a relatively small fraction (1.8%) of deaths are coded to this category and the effect on road injury death counts is thus expected to be small. 

Second, we have made no adjustments to account for incomplete death registration because estimates of completeness of global death registration data are currently being developed. However, our preliminary comparison of total all-cause deaths reported in the death registration data analyzed by us with deaths reported by the UN Population Division suggests that death registration in Slovenia is near complete. It should be noted that both of these adjustments would increase the estimated death counts. Thus, the mortality results presented here likely underestimate the true number of road injury deaths.

Comparison of our estimates with other sources

Our estimate of road injury deaths in Slovenia are similar to those reported by official government statistics in the 2009 WHO Global Status Report on Road Safety (Figure 3). 

Road deaths by age and sex

Most road deaths occur among adult males (Figure 4a). Almost 3/4th (73%) of all road injury deaths were men and most of these men (90%) were adults older than 20 years. Death rates (Figure 4b) among men are over three times higher than those among women overall. Men have higher death rates for all age groups but the gender differential is smaller among the elderly.  Both death counts and death rates rise dramatically in the transition in age from childhood to young adults (see age groups 10-14 years and 15-19 years). Death rates are highest among the elderly. 

Such age and sex patterns in deaths and death rates are consistent with those seen in other countries. For the most part, the gender differentials in death rate are a result of higher exposure to road traffic among men in combination with higher risk-taking behavior. Similarly, the age pattern of death rates partly reflects patterns of exposure and partly case-fatality rates. While exposure to road traffic declines with age among older populations, the bio-mechanical tolerance to injury (i.e. the likelihood of death in the event of a crash) also declines, resulting in increasing death rates with age. 

Road deaths by type of road-user

Half of road deaths in Slovenia occur among car occupants (Figure 5).  Pedestrians and  motorcyclists comprise an additional 16% each. 

Although motorcyclists currently rank second in the road death tally in Slovenia, they are a special concern. Our analysis of data from recent years suggests that while deaths among pedestrians, car occupants, and bicyclists are declining in Slovenia, much of these road safety gains are being lost because of a growing number of deaths among motorcyclists.  Motorcycles are already known to comprise a large portion of the vehicle fleet (and road death toll) in other regions, specially South-East Asia. However, we have found a rapidly rising trend in road deaths in several other regions, including Latin America (see, for instance, our analysis of road injuries in Brazil) and Central Europe (see, for instance, our analysis of road injuries in the Croatia). This analysis of road deaths in Slovenia suggests that motorcycles pose a similarly growing risk in this country as well.  See attached web tables (Slovenia-WebTables) for time-histories of road deaths by road-user type.

Estimates of non-fatal road injuries

The incidence of non-fatal road injuries can be estimated from various sources, including police reports, hospital administrative records, and population surveys. Among these, police reports are widely known to underreport road injury cases in low income countries as well as in high income countries. Hospital records have the advantage of providing detailed medical descriptions of injuries making classification of injuries by severity possible. However, estimation of population rates is difficult without investing substantial efforts in identifying the hospital catchment population. Thus, population based health and injury surveys are the most reliable sources of information for incidence of road injuries, especially in information-poor settings.

We estimated the incidence of non-fatal road injuries in Slovenia using the 2002-2003 World Health Surveys (WHS), a nationally represented household survey that included questions on road injury involvement. These surveys, which were conducted by the World Health Organization, provide a unique opportunity for cross-country comparisons of non-fatal injuries because they asked the same set of questions in 53 countries, most of which are low- or middle- income countries. The surveys included the following set of road injury related questions in their household module:

In Slovenia, 585 interviews were conducted as part of the WHS, with a response rate of 86% and only 1.7% of the surveys had missing responses for the question on bodily injury in road accidents. In our analysis of the WHS, we replaced the missing values for this question with the predicted value from a logistic regression model fit to the cases with a non-missing response. The model used the response to this question as the dependent variable and the following independent variables: gender, age groups, place of residence, permanent income quintile, country, marital status, education, occupation, self-rated health, visual acuity (seeing and recognizing a person from across road), and alcohol consumption as predictor dummy variables. We used survey (svy) commands in Stata 10 for the analysis of the WHS.

Non-fatal injuries by age, and sex

Our analysis of the 2002/2003 WHS suggests that almost 56,000 people in Slovenia are involved in non-fatal road crashes annually. This corresponds to 2.8% [95% CI:1.4 -4.1%] of the population. 

While men have higher rates of non-fatal road injury incidence than women, the difference is not statistically significant (Figure 6).  Road injury incidence is higher among young adults (18-44 years) than among those that are older, but the differences are not statistically significant (Figure 7).                     


These country reports were produced as part of a project funded by the World Bank Global Road Safety Facility. The results presented here are based on secondary data analysis of data collected by various national and international agencies.