As part of the ongoing International Study of Highway Development and Management Tools (ISOHDM), an evaluation was undertaken by TRL of the current ability to predict changes in accident rates in developing countries following modifications in road design. This paper summarises the work carried out as part of the ISOHDM Study and presents a review of work conducted in the developing world together with the lessons learned from developed countries' experiences in this field. It should be noted that the very different features of road and traffic conditions in developing countries, (e.g., high pedestrian and non-motorized vehicle usage, conflicting land uses, and road user behaviour), substantially limits the potential for transferring information from industrialised countries to the developing world. The current ISOHDM Study offered an opportunity to evaluate the present ability to incorporate accident costs and benefits into highway investment modelling in developing countries. Accordingly, this paper reviews the work over the past two decades investigating the relationship between road geometry and accident rates relevant to developing countries. Several developing country case studies are reviewed and their results compared. A summary of the role of safety benefits in road appraisal methods in industrialized countries is also analysed to provide guidance for developing countries. (A)
Abstract