Investment decisions on road safety measures, such as road design improvements, promotion campaigns, enforcement activities and research prioritisation, require implicit or explicit values for accidents avoided in order to distinguish which investments provide the most worthwhile application of limited available resources. While the broad components of the social cost of accidents have been recognised for many years, the valuation of these separate components requires techniques of varying practicality, leaving estimates incomplete. This paper describes research over the past ten years aimed at putting valuation estimates on a sounder, more consistent basis. Starting with the theoretical debate of economic valuation of human casualties, which culminated in 1991 with New Zealand's replacement of the human capital approach to valuing casualties with a social-survey derived value based on willingness to pay for reduced risk, the paper traces subsequent development of techniques to measure separate components of the social cost of accidents, and means of indexing values over time. It reviews the values currently used and adopted in official assessment of road safety measures in New Zealand, and considers exercises still in progress to estimate the more difficult components, such as the value of output loss, medical costs and accident-induced traffic delays. (a) For the covering entry of this conference, please see ITRD abstract no. E202275.
Samenvatting