Iglad - International Harmonized In-depth Accident Data

An important method for the development of strategies and measures to prevent accidents and mitigate the injury severity is the analysis of accident databases. However, the variety of research questions requires different kind of information. To assess accident situations, examine trends, or similar analysis, databases at a base level such as national statistics are available for many countries. On the other hand, the identification of accident and injury causation and the evaluation of countermeasures require a higher level of detail. For this reason, several in-depth accident data collection projects emerged worldwide in recent years. Unfortunately, due to different standards for data collection and coding comparative analysis of in-depth data from different countries is difficult or even impossible. This paper describes the approach taken by the IGLAD (Initiative for the Global Harmonization of Accident Data) project to handle these shortcomings by using a common data scheme and investigates the opportunities and limitations for weighting and extrapolation to national statistics. The methods used to process and merge the different data samples are described and an overview of the current status in terms of case counts, marginal distributions and the participating countries from Europe, Asia, Australia and North and South America providing data for the project is given. As an application example, the IGLAD dataset with accidents from 2007 to 2015 was used to analyze the distributions of accident types, presence of safety systems, characteristics of injury severity for each country and provide country comparisons. Also capabilities for pre-crash analysis were assessed. As a result, exemplary statistical assessment of injury probability, descriptive statistics for comparison between different countries were given as a result of the analysis. A pilot study about a more detailed analysis of the pre-crash phase has already been conducted which would allow for analysis of the potential benefit of safety systems in different countries. The authors discuss limitations, special characteristics and bias of the data samples from the individual countries. An outlook is given on the future development of the project, now preparing its fourth data release and on further extension of the data. Summarizing, the paper gives an overview of IGLAD as a new field crash data set and shows its unique opportunities for road accident analysis in a global scope, which are not provided by any other accident data source.