Valuation of road safety effects in cost–benefit analysis

Cost–benefit analysis is a common method for evaluating the social economic impact of transport projects, and in many of these projects the saving of human lives is an issue. This implies, within the framework of cost–benefit analysis, that a monetary value should be attached to saving human lives. This paper discusses the ‘Value of a Statistical Life’ (VoSL), a concept that is often used for monetising safety effects, in the context of road safety. Firstly, the concept of ‘willingness to pay’ for road safety and its relation to the VoSL are explained. The VoSL approach will be compared to other approaches to monetise safety effects, in particular the human capital approach and ‘quality adjusted life years’. Secondly, methods to estimate the VoSL and their applicability to road safety will be discussed. Thirdly, the paper reviews the VoSL estimates that have been found in scientific research and compares them with the values that are used in policy evaluations. Finally, a VoSL study in the Netherlands will be presented as a case study, and its applicability in policy evaluation will be illustrated.