CADaS - The Common Accident Data Set

Deliverable D1.14 of the EU FP6 project SafetyNet


Yannis, G.; Evgenikos, P.; Chaziris, A.; Broughton, J.; Lawton, B.; Walter, L.; Hoeglinger, S.; Leitner, T.; Angermann, A.; Bos, N.; Hemdorff, S.; Hollo, P.; Tecl, J.; Rackliff, L.; Sanmartin, J.; Pace, J.-F.



SafetyNet is an integrated project that aims to bring together a wide range of accident data and related information to support National and EU level road and vehicle safety policy. When completed, the combined set of information will be available to the public over the internet to form a core element of the EU Road Safety Observatory.

Within Work Package 1 (WP1) of the SafetyNet Integrated Project, one of the project's seven Work Packages that deals with the further enhancement and exploitation of the CARE accident data, the improvement of accident data compatibility throughout Europe was attempted. As harmonisation of accident data at national level (apart from the EC level) could be very beneficial for road accident analysis, using more common variables and values across the European countries, a Common Accident Data Set (CADaS) and methodology were established, to be used by any EU country that wishes to update their national road accident collection system.

In order to develop this recommendation for a Common Accident Data Set, three main activities were under way during the Task 1.4 duration: Initially, information on existing national road accident data collection systems was gathered, allowing for the exploitation of available experience, but also the identification of any specific requirements in some countries. National road accident data collection forms, methodologies and data definitions from all EU countries were gathered through the members of the CARE Experts Group, with the assistance of the European Commission, and also a relevant questionnaire was developed and filled-in by representatives from almost all EU countries. Processing and analysis of this information allowed for the recording of the current potential of all EU national data collection systems.

At the same time, the needs of the main stakeholders in different EU countries were identified, in order to define the necessary data for road accident analysis. According to the specific circumstances in each country and the specific needs of each stakeholder, different needs were expected to be recorded, thus this activity took place at both national and local level. The main interest groups were Public Services (Police, Hospitals etc), Central Governmental Authorities (Transport, Health), Local Governmental Authorities, Research Institutes and Industry (including transport associations). An appropriate Grid was developed to establish a list of various stakeholders by country and then identify their needs for accident data. By filling-in this Grid for several stakeholders, the maximum needs were defined for each country and these were further compared, in order to identify the minimum/common needs for all countries examined.

On the basis of the outcomes of the above mentioned activities, the national collection systems from all EC member states were analysed and through an iterative process, taking into account both data availability and usefulness, but also variables and values of CARE and the experience of other international data files (US - MMUCC, WHO) the recommendation for a Common Accident Data Set was formulated, consisting of a minimum set of standardised data elements, which will allow for comparable road accident data to be available in Europe. In this way, more variables and values with a common definition will be added to those contained in the CARE database, maximising thus the potential of CARE database and allowing for more detailed and reliable analyses at European level.

This set of data to be voluntarily transmitted by each country to the EU, will be derived from the national road accident data collection system, it can be implemented on a voluntary basis at the national accident collection systems and will be gradually adopted by the EU countries. It is structured in a simple way, without levels of hierarchy, constituting in fact the record layout of the data set to be transferred to the EU. Moreover, the structure of the CADaS variables allows for various levels of detail to be selected for providing the requested data, by the use of alternative (aggregate) values.

CADaS consists of 73 variables and 471 values. The selection of these variables and values resulted from the balanced co-consideration of some basic criteria, taking into account that variables and values must be comprehensive, concise and useful for road accident analysis at EU level, the level of detail of the variables and values should correspond to all data useful for macroscopic data analysis and that each country should have the possibility to choose alternative level of detail of the various variables and values. Data which are impossible or very difficult to be collected are not retained in the CADaS, however, the future perspective of using certain variables and values was also taken into account, even though those data are not currently collected by most of the countries. Existing CARE variables and values are of first priority within CADaS and additionally, CADaS variables and values refer to casualty road accidents.

The CADaS variables are divided into four basic categories: Accident related variables, Road related variables, Traffic unit related variables and Person related variables. Several variables include two distinct types of values, referring to different level of detail: Detailed values, concerning information at the highest level of detail and alternative values, concerning information at a more aggregate level of detail, when more detailed values are not available.

The adoption of this recommendation by the European countries is very important to guarantee the success of this Task. CADaS can be adopted gradually by EU countries, but any part of it (variables, values, definitions and data formats) can be implemented within an existing national system, increasing the compatibility of national data with the respective CARE data. Subsequently, the level of adoption of the CADaS can vary according to any national needs and/or particularities and can be performed during any time in the future. Certainly, if one country wishes to enhance its national accident data or change its national system according to the CADaS protocol, it can adopt the CADaS proposal in pieces ("à la carte" system) or as a stand alone road accident data collection system.

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