How would setting policy priorities according to cost-benefit analyses affect the provision of road safety? 
This paper analyses how setting priorities for road safety strictly according to cost-benefit analysis would affect the provision of road safety in Norway and Sweden.  The paper is based on recent analyses of the efficiency of road safety policies in these two countries.  The argument sometimes made by critics of cost-benefit analysis, that only a few road safety measures are cost-effective (have benefits greater than costs), is not supported.  Cost-effective road safety policies could prevent between 50 and 60% of the current number of road accident fatalities in both Norway and Sweden, if pursued consistently during a period of 10 years (2002-2011).  If current policies are continued, only about 10-15% of the current number of road accident fatalities are likely to be prevented during the next 10 years.  A number of sources of inefficiency in road safety policy are identified.  A source of inefficiency is anything that prevents policy priorities from being set according to cost-benefit analysis.  These include: (a) lack of power, which means that national governments do not have the formal authority to introduce a certain road safety measure, in Europe, this applies to new vehicle safety standards, which are passed almost exclusively by the European Union; (b) the existence of social dilemmas, which means that measures that are cost-effective from a societal point of view are not so from the point of view of individual road users; (c) priority given to other policy objectives, in particular regional development.  Scarcity of resources, which obtains when public budgets have to be increased to make room for all cost-effective measures, was not found to be a constraint.  All cost-effective measures can be funded within current budgets, provided the use of inefficient measures ceases.