Report numberRA-MOW-2011-022
TitleThe Road Accident Analyzer
SubtitlePart III: Manual and case-study E313
AuthorsKoen Van Raemdonck
Cathy Macharis
Published byPolicy Research Centre for Mobility and Public Works, track Traffic Safety 2007-2011
Number of pages53
Document languageDutch
Partner(s)Vrije Universiteit Brussel
Work packageOther: Reference database for research into traffic safety in Flanders

This report explains the functioning of a GIS-tool, called the Road Accident Analyzer (RAA), which was developed to identify dangerous road segments on the road network. In fact, the report is a manual for the use of the RAA, in which the necessary input data, the process and the results are explained stepwise for each methodology by means of a case-study of the E313. The different methodologies used by the RAA to identify dangerous road segments are the following:

  • Accident density;
  • Accident risks;
  • The Empirical Bayes approach.

Each of these methodologies has some advantages and disadvantages. The first method for example, is very straightforward and easy to use, but it neglects some important explanatory variables for the occurrence of traffic accidents (such as traffic volume). The second method however is capable to include those road characteristics in the analysis, but assumes that the number of accidents and traffic volume are linearly related. The third method is considered as the state-of-the-art, bit is also more complex in comparison with the other methodologies. Next to the manual for the use of each methodology, these advantages and disadvantages are also being listed in this report.


Finally, a sensitivity analysis on the weights which are used to include injury severity into the analysis is also carried out. 4 scenarios, similar to previous research within the Policy Research Centre of Mobility and Public Works – track Traffic Safety, are being investigated:

  • 1_1_1 in which each accident is evenly important;
  • The weights that are currently used in Flanders (1_3_5);
  • 1_1_10 in which the focus is on deadly accidents;
  • 1_10_10 in which mainly accidents with fatally and severely wounded victims should be avoided.
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The Policy Research Centre for Traffic Safety carries out policy relevant scientific research under the authority of the Flemish Government. The Centre is the result of a

cooperation between Hasselt University, KU Leuven and VITO, the Flemish Institute for Technological Research.


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