Safety measures are classified on the basis of two criteria. The first criterion is related to 'factors contributing to accidents'- the road user, the vehicle and the road. The other criterion relates to the safety characteristic changed, namely exposure, risk or accident consequence. The final decision on which safety countermeasure should be preferred should in each case be taken on a cost-benefit basis.
Elvik (1997) also thinks that cost-benefit analysis will become increasingly important in the field of road safety decision-making. One reason is the limited financial resources that will be available for road safety. Funds should therefore be applied as efficiently as possible. Another reason is that more and more often a choice will have to be made between competing objectives, which could be environmental or based on mobility, energy or safety. Converting conflicting objectives to an economic yardstick is one way of treating problematic decisions.