The cost of road crashes in the Netherlands : an assessment of scenarios for making new cost estimates.

Wijnen, W. Schroten, A. & 't Hoen, M.

The latest estimate of the costs of road crashes in the Netherlands was made for the year 2009. The Ministry of Infrastructure and Environment has the ambition to launch a study to make new cost estimates. It is recognised that the methodology used in that study needs to be revised, but also that a trade-off needs to be made between on the one hand the cost of developing a new methodology and on the other hand the resulting quality of the cost estimates based on this new methodology. This study presents the information needed to make this trade-off, based on a thorough assessment of various research scenarios to update the current methodology. A review of the international state-of-the-art of estimating road crash costs shows that the Dutch methodology is generally in line with international guidelines and practices. Almost all main cost items that are recommended by international guidelines are included. The main omission is the human cost of slight injuries, which was missing in the previous Dutch studies on road crash costs. As the expected impact of this omission on total costs of road crashes in the Netherlands is substantial, it is recommended to add this cost item in a new study. Other relevant cost items that could be added to the current methodology include costs of non-market production (e.g. household work), damage to road infrastructure, administrative costs of health insurances and costs of vehicle unavailability. Although the methodology used in the Dutch studies on road crash cost are to a large extent in line with international guidelines and practices, there are still several needs to improve the methodology uses. Particularly the quality of data that were used is a severe weakness of the current methodology. Estimating road crash costs requires many input data on both unit costs and casualty information, and for several cost items outdated data were used. This concerns relatively large cost items, such as human cost of fatalities, production loss and vehicle damage. An update of these data is recommended to substantially improve the accuracy of the estimate of the costs of road crashes. For some cost items, the quality of the methodology could be improved as well. This particularly concerns the human costs of serious injuries, which are currently based on a simple value transfer of estimates found in international literature instead of a country-specific study for the Netherlands. In this study we analysed several scenarios for a new cost study in the Netherlands, ranging from very simple approaches (cost are updated by using inflation correction and new road safety statistics only) to extensive methodological improvements. The assessment shows that there is no superior approach, that is clearly preferred to all other approaches. More simple approaches have the advantage of having low cost, but they provide less improvements with respect to the quality of the cost estimates and the resulting quality of the cost estimates is poor. On the other hand, more sophisticated approaches do provide much better quality estimates, but their costs are significantly higher. The relationship between the costs of improving the cost estimates and the quality improvement is found to be quite linear. This is illustrated in Figure 1. The implication is that the available budget determines the quality that can be achieved and that within a given budget the highest quality of cost estimates should be looked for. Available resources should, therefore, be spent on cost items that have the most significant impact on total costs and which can be improved in the most efficient way. Next to a large-scale update of the data used, this concerns methodological improvements for cost items such as human costs of injuries, market production loss, unreported vehicle damage and human costs of fatalities. Collaborating with other countries could increase the possibilities to improve the methodology, particularly since the costs of methodology development can be shared in such a scenario. Better comparability of costs estimates across countries is an additional advantage. The main option to realise international cooperation is an international project initiated and funded by (possibly multiple) national governments. A broad inventory under representatives of international organizations shows that information on costs is considered as very important for road safety research and policy making, and that there may be support for such an initiative. However, such a project would require substantial efforts and can probably only be launched on a longer term. Therefore, a phased approach may be attractive: in a first step a new study could focus on cost items that require relatively limited resources or are less suitable for international cooperation (e.g. medical costs, administrative costs), while in a second step more sophisticated methodologies may be developed in an international project to update the other cost items (e.g. human costs of casualties and injuries). (Author/publisher)


20170413 ST [electronic version only]

Delft, CE Delft, 2016, 102 p., ref.; Publicatienummer 16.7J25.117

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