Use of accident prediction models in road safety management – An international inquiry

Evaluation of road safety measures appears to be the weakest component of road safety management systems in Europe. To improve Road Infrastructure Safety Management, road authorities, road designers and road safety practitioners need prediction tools, commonly known as Accident Prediction Models (APMs), allowing them to analyze the potential safety issues, to identify safety improvements and to estimate the potential effect of these improvements in terms of crash reduction. Within the above context, the objective of this paper is to present a synthesis of current practices in APMs based on both the results of a relevant survey and an extensive literature review conducted within the PRACT project. In order to present a complete overview of currently used Accident Prediction Models (APMs) by different National Road Administrations (NRAs) in Europe and worldwide, as well as the currently used data sources for the development and application of APMs a relevant survey was completed. A questionnaire was specially designed and dispatched to several NRAs in Europe and worldwide, in order to collect detailed information on APMs developed and used by them. Furthermore, a review of relevant international literature was carried out, with focus particularly on identifying those modelling approaches and specific models that may be applicable or transferable in the European context. On the basis of the questionnaire data and of the literature review results, a synthesis of current practices regarding APMs has been developed, as a basis for the identification of the most usable models as well as for the implementation of a web based APM repository. In total, 23 questionnaires were collected from 18 European countries, USA and Australia, and were analysed with the aim of reviewing and assessing existing APMs, in terms of theoretical approaches, characteristics of the models in use, implementation conditions, data requirements and available results, with focus on motorways and higher ranked rural roads. It was found that, despite recent advances, most National Road Administrations (NRAs) and other organisations do not systematically use such methods during decision making for the implementation of road safety treatments.