Speed is an important factor of road accidents. This paper focusses on changes and differences in speed of the traffic flow and on speed differences between different vehicles. Based on an international literature survey the relevance of the speed related factors for road safety are described. Road categorization and delineation of speed limit zones are identified as the most important tools to obtain a more homogeneous speed pattern. Based on a series of case studies including the different urbanization typologies, it is shown that regarding the implementation of these two planning concepts, little has been achieved in Flanders. The scattered and ribbon shaped urbanization along the secondary and local roads and the step by step adaptation of speed limits on road segments by the different road authorities, give rise to a manifest lack of homogeneity . Based on the Flemish Road Signs Database a quantitative analysis (e.g. relating to the length of segments, number of speed limit changes on a road section, etc.) could be carried out. The database contains all traffic signs relevant for speed limits on the entire road network in Flanders, including the road sign position and the description of its characteristics. Based on the case studies both an analysis of the existing situation as well as an explorative assessment of a generic scenario (entering a general speed limit of 70 km/h in non-built up areas instead of the current limit of 90 km /h were described. By implementing this scenario, six out of seven speed limit signs can be removed and the workload for the drivers can be reduced proportionately. So speed limit policy and zoning can be regarded as key instruments for more road safety on local and secondary roads.

road safety, speed limits, Flanders Region, secondary roads, traffic signs database