The Value of Fatal and Non Fatal Road Accident Reductions
J de D Ortuzar, P Hojman, L I Rizzi, Pontificia Universidad Catolica de Chile, CL
To evaluate the benefits of transport safety projects we must have values associated to road accident reductions. A correct microeconomic approach to obtain such values entails the use of individual preferences. The usual way to obtain these values is through contingent valuation, i.e. to ask respondents to put a price on very low risk reductions, a situation which is completely unusual to most people. On the other hand, the values due to risk reductions in the case of fatal and non fatal accidents are usually obtained in separate ways producing an aggregation problem. To improve on both these weaknesses in the state of practice, we set up a novel stated preference survey in which individuals had to chose between two routes for a hypothetical trip between two large cities. The routes differed in travel time, toll charge, number of fatalities and of severely injured victims per year. This way, respondents had to state their preferences for safety in an implicit way, both in terms of the reduction in fatal and severely injured victims. The data gathered was used to estimate discrete choice models allowing us to obtain values of approximately US$500,000 and US$70,000 for one reduction in the number of fatalities and severely injured victims respectively; these are eminently plausible values. We also derived subjective values of time completely consistent with values obtained in previous studies; this confirmed our belief that respondents both understood the exercise and answered it seriously.
Association for European Transport