The traffic system and cultural dissimilarities are believed to contribute significantly to regional and country differences in road safety performance. Therefore, caution is required when transferring safety management and intervention tools from one region to another. This report deals with the application of two safety evaluation tools, developed at the Laboratório Nacional de Engenharia Civil in Portugal and at the Technical University of Dresden in Germany, to a set of road stretches in both countries. The procedures analysed are intended for the detection of inconsistent horizontal curves and dangerous non-intersection sites. The main questions investigated are related to the direct applicability of both methods outside the region where they were developed. This was investigated by means of a comparison of the detected danger and non-danger zones identified with each method and the corresponding accident rates and by direct comparison of the danger classifications obtained with both methods. Geometric and traffic data on 42 km of Portuguese roads and 190 km of Brandenburg roads were analysed. Data on traffic and registered accidents refer to a four year period in Portuguese roads (1147 accidents) and a three year period in Brandenburg (126 accidents). The main conclusions are that both methods need further recalibration to local conditions, in order to fully take advantage of their potential. When properly used, both methods effectively assist road designers in detecting high accident risk sites at the design stage; however, they are not so successful at discarding low accident rate sites from further safety analysis. Despite incorporating variables intended to represent driver behaviour, there is still a considerable percentage of high accident rate sites not being identified as deserving further study and safety improvements in both methods, indicating that their effectiveness may be improved. (Author/publisher)
Samenvatting