Benefits of area-wide traffic calming measures: outcomes still to assess

The role of traffic calming schemes in urban network management is mainly to minimize undesirable effect of traffic in residential areas; in this context accident reduction can be a realistic objective. Several studies, indeed, inform us that traffic calming is a major part of the treatments available to reduce road accidents in urban areas. Paradoxically the increase of the accident rate per kilometre travelled has been observed in the urban context as result of the wellknown accident migration phenomenon. In connection to these considerations, the effectiveness of traffic calming measures on road safety is discussed in this paper. Then, after a synthetic exposition of the conceptual formulation and the potential of the meta-analysis method in detecting the true safety effect of traffic calming measures, the paper also considers the role of the road network planning and the characteristics of urban network that have to be consistent to the traffic calming objectives. At last, a methodological framework to follow for the implementation of traffic calming schemes in residential areas, from the planning level to the road design one, is proposed.