Economic evaluation of road safety measures - Swov

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6.2. Set up of the cost-benefit analysis Finally, a special complication needs to be mentioned. Sometimes measures that have important side effects on traffic safety are taken in other sectors. An example of a measure with a strong positive effect on traffic safety has been the construction of the motorway network. A sharp increase in public transport fares is another example, this time with a negative effect. These measures cannot be taken into account when developing traffic safety policy since they are meant to solve an entirely different problem. However, awareness of side effects on traffic safety could be promoted in other relevant sectors during decision making processes. A CBA for the entire traffic safety policy sector cannot easily be compared with previously mentioned examples of CBAs (i.e. the one of the second national airport). An important difference is that here a complete policy sector is being evaluated in the form of alternative packages of measures or programs. The assumption is that these programs have been developed, using existing knowledge, with a definite vision on the improvement of road safety. Each alternative program will therefore have a certain internal cohesion and be deemed effective through the combination of measures. The alternatives differ in the composition and/or the extent of the packages. An evaluation that investigates the costs and benefits of each separate measure has little point. No single measure is meant to be implemented separately, it is always in combination with other related measures. Furthermore, it concerns an assessment of the sector as a whole; a highly detailed evaluation of all the separate elements will exceed its goal. The following steps can be distinguished in implementing the CBA: - estimation of the implementation costs of each program; calculation of the present value based on distribution over time - estimation of the intended effects, i.e. less victims (differentiated by seriousness) and physical damage to vehicles, roads and road facilities; given as a distribution over time - estimate of unintended effects, direct or indirect, each expressed in their own units; similarly given as a distribution over time - assessment of the intended, side and indirect effects in monetary terms; calculation of the present value of the effects based on their distribution over time - calculation of the ratio of the present value of costs and benefits (CBR) (or the IRR). A number of conditions have to be met to implement these steps: sufficient information about implementation costs and their distribution over time; sufficient knowledge about the extent of the various types of effects and their distribution over time; and an acceptable method for assessment of these effects in monetary terms. One part of these conditions therefore concerns quantifying the effects; another part deals with appraising the effects. Both of these will be looked at in more detail below. Quantifying the program costs in this respect will not be discussed. 30 SWOV Publication D-2000-16E
6.3. Quantifying effects Whether there is sufficient information available to quantify effects is mainly determined by the packages being evaluated and the measures that they include. It should be assumed that no research has been done into the effectiveness of the packages put together for this goal, but certainly into a number of the separate measures. The effectiveness of packages therefore has to be assessed on the basis of expert judgement, using knowledge about the effectiveness of individual measures. The distribution of effects over time also has to be estimated in this way. A complication is that many traffic safety measures are adopted whose direct intended effects do not aim to reduce the risk or seriousness of an accident. This reduction can be a, sometimes highly remote, indirect effect of these measures. This is clear in the following overview of measures that often appear in traffic safety programs: - people-oriented measures like information, education, training, legislation and enforcement. The direct intended effects consist of certain changes in behaviour (fewer speeding violations, increased seat belt use, changing the speed of approach at junctions, less driving under the influence etc.) or a change in knowledge and attitudes (knowledge of right of way regulations, taking broader risk margins when overtaking etc.) - infrastructural measures such as dividing the road network into functional categories and bringing the design of each category into accordance with its function (e.g. the design of junctions and connections with side roads, the presence of safety constructions). The direct intended effects in this case are usually a reduction in the risk of accident (e.g. measures that inhibit speed) or the seriousness of an accident (like a crash barrier) - vehicle-oriented measures like legal requirements for construction and maintenance (e.g. crushable zones, minimum tyre depth, periodic testing) or the presence of safety features (e.g. speed limiters, automatic switch for daytime running lights, seat belts, air bags). The direct intended effects are also a reduction in the risk of accident or the seriousness of one - post-crash measures like faster alert systems (emergency telephones), faster assistance (helicopter), trauma teams in hospitals. The direct intended effect here is a reduction in the seriousness of the outcome of accidents (timely stabilizing of a patient's condition, faster recovery, fewer long-term consequences) - facilitating measures such as the organization of traffic safety policy (decentralization of responsibilities to lower management levels), education and information to create the basis for new policy, gathering knowledge (research, monitoring) and distributing existing knowledge amongst professionals. The direct intended effects are more effective and efficient policy management, support for new measures, increase in scientific knowledge and insight, expanding the professional expertise of people preparing policy. To be able to conduct a CBA, the intended indirect effects of peopleoriented and facilitating measures on safety will have to be estimated along with their distribution over time. If it concerns second order effects, this is likely to be successful; the relationship between behaviour and the risk of SWOV Publication D-2000-16E 31
Page 1: Economic evaluation of road safety
Page 4 and 5: Report documentation Number: D-2000
Page 7 and 8: Contents Acknowledgements 6 1. Intr
Page 9 and 10: 1. Introduction The lack of road sa
Page 11 and 12: euro test'. This requirement exists
Page 13 and 14: Consumer behaviour theory tries to
Page 15 and 16: therefore also refer to them as 'in
Page 17 and 18: aptitude and physical ability), and
Page 19 and 20: 5. Evaluation methods 5.1. Introduc
Page 21 and 22: Caution must be exercised to avoid
Page 23 and 24: circumstances, the combination of a
Page 25 and 26: 5.4. Cost-effectiveness analysis Th
Page 27 and 28: 5.5.2. Multi-criteria methods Once
Page 29 and 30: In applying either method, it is no
Page 31: Looking at the profitability of alt
Page 35 and 36: - medical costs - loss of productio
Page 37 and 38: 7. Composition of packages of measu
Page 39 and 40: 8. Conclusions and recommendations
Page 41 and 42: References Alfaro, J.-L., Chapuis,

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