Costs and benefits to Sweden of Swedish road safety research

Costs and benefits to Sweden of Swedish road safety research

Accident Analysis and Prevention 41 (2009) 387–392 Contents lists available at ScienceDirect Accident Analysis and Prevention journal homepage: www...

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Accident Analysis and Prevention 41 (2009) 387–392

Contents lists available at ScienceDirect

Accident Analysis and Prevention journal homepage: www.elsevier.com/locate/aap

Costs and benefits to Sweden of Swedish road safety research Rune Elvik a,∗ , Marika Kolbenstvedt a , Beate Elvebakk a , Arild Hervik b , Lasse Bræin c a

Institute of Transport Economics, Gaustadalléen 21, NO-0349 Oslo, Norway University College Molde, PO Box 2110, NO-6402 Molde, Norway c Møre Research Molde, Britvegen 4, NO-6411 Molde, Norway b

a r t i c l e

i n f o

Article history: Received 13 April 2007 Received in revised form 9 December 2008 Accepted 27 December 2008 Keywords: Road safety Research Evaluation study Sweden Long-term trends

a b s t r a c t This paper summarises a study designed to answer the following question: what are the benefits to Swedish society of road safety research in Sweden funded by the Swedish Transport Research Council and the programme for vehicle safety research during the period 1971–2004? The paper starts by discussing whether research can answer this question at all and explains why a well-controlled study was not feasible. A case study approach was selected, and five major research projects were examined in detail for the purpose of trying to estimate their effects on road safety. Estimates of safety effects were developed for four of the projects, indicating that road safety measures that were at least to some extent based on the findings of the research projects have made major contributions to reducing the number of road accident fatalities in Sweden. The estimates are not analytically rigorous and should be treated as qualified guesses only. Causal inferences are not possible. Nevertheless, if taken at face value, they show that the benefits to society of road safety research are large and outweigh by a wide margin the costs of the research, and of the road safety measures developed as a result of research. Thus, even if the estimated safety benefits exaggerate the true effects, the benefits of applied road safety research are likely to be greater than the costs of conducting this research and implementing road safety measures developed by research. © 2008 Elsevier Ltd. All rights reserved.

1. Introduction The task given to the study presented in this paper was stated by its sponsor as follows: what are the benefits to society of road safety research in Sweden funded by the Swedish Transport Research Council and the programme for vehicle safety research during the period 1971–2004? Researching the study question was challenging. Although road safety research is an applied field of knowledge, because the transport system constantly changes and accidents are influenced by literally hundreds of factors, it is difficult to isolate the effects of specific road safety measures. Furthermore, the causal chain starting with the production of knowledge and ending by the successful application of that knowledge is often more complex than in those few cases when inventions with easily detectable benefits are made. Road safety research is not characterised by the sudden invention of miracle vaccines that make the problem go away. It is more aptly described as a field in which “knowledge tends to come in small doses” (Hauer, 1983). Besides, road safety policy and long-

∗ Corresponding author. Tel.: +47 22 573800; fax: +47 22 609200. E-mail addresses: [email protected] (R. Elvik), [email protected] (M. Kolbenstvedt), [email protected] (B. Elvebakk), [email protected] (A. Hervik), [email protected] (L. Bræin). 0001-4575/$ – see front matter © 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.aap.2008.12.009

term trends in road safety are influenced by many factors, not just research. Several approaches that can be taken to a study aiming to estimate the costs and benefits of road safety research were considered, but judged not to be feasible. A before-and-after study was ruled out, since no clearly designated before- or after-periods exist. Besides, controlling adequately for potentially confounding factors was regarded as impossible. Time-series analysis was also ruled out. There were no clearly discernible changes from year-to-year in research funding that could be linked to corresponding changes in road safety. Besides, implementing road safety measures based on research is likely to involve considerable, often unknown, lags in time. Comparing Sweden to other highly motorised countries in terms of road safety performance was rejected, as all countries to which it is reasonable to compare Sweden have also carried out extensive road safety research that Sweden may have benefited from, irrespective of its own research effort. Finally, an econometric analysis of variables influencing road safety was rejected as there are only 35 years of data, which makes it impossible to fit anything but a very simple model containing a few variables. A case study approach was adopted. The cases selected for detailed study were, with one exception, cases for which extensive previous evaluation studies existed and for which the causal chain going from the production of knowledge to the improvement

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of road safety was judged to be sufficiently well known to support quantitative estimates of the benefits of research. The outcome measures used in the study were changes in the number of fatalities and injuries and monetary valuation of these changes. 2. The case study approach Cases were selected from a database of research projects. All research projects in this database were funded by the Swedish Transport Research Council, which existed under different names from 1971 to 2000, or by VINNOVA, taking over the functions of the Transport Research Council in 2001. Care was taken to select cases whose history could be reconstructed in some detail by means of evaluation studies or interviews of researchers or representatives of the funding body. The criteria for selecting cases were: (1) cases represent research whose quality is recognised by the academic community, i.e. the main findings have been published in scientific journals following peer review. (2) Cases lead to the development or increased use of road safety measures whose effects have been evaluated according to accepted scientific standards. (3) Cases were selected to include all four major institutions performing road safety research in Sweden (identified below). The following cases were selected: 1. Research on urban safety management at the Lund Institute of Technology, in particular a project in Växjö, designed to reduce speed in inner cities (Hydén and Várhelyi, 2000). 2. Research on child restraints at the Swedish Road and Transport Research Institute (VTI) and Chalmers Technical University (Aldman, 1962; Carlsson et al., 1987; Tingvall, 1987; Turbell et al., 1993; Isaksson-Hellman et al., 1997). 3. Research at Chalmers on neck injury protection and side impact protection (Håland, 1994; Viano and Olsén, 2001; Braver and Kyrychenko, 2003; Eriksen et al., 2004). 4. Research on police enforcement at VTI and the Department of Psychology, Uppsala University (Nilsson and Åberg, 1986; Nilsson and Engdahl, 1986). 5. Research conducted by means of the driving simulator at VTI (Törnros, 1998).

Fig. 1. Road accident fatalities in Sweden from 1970 to 2005.

accident fatalities in Sweden has declined from 1307 in 1970 to 440 in 2005, analysis focused only on factors that might explain this decline, not on factors that might lead to an increasing number of fatalities, although such factors have been present throughout the period. The following sections briefly explain how the effects of various factors were estimated. Complete details are found in the main report from the study (Kolbenstvedt et al., 2007). The following factors were included: 1. Reduction of travel performed by pedestrians, cyclists and moped riders. 2. Reduction of travel performed by young drivers. 3. Construction of motorways (freeways). 4. Construction of 2 + 1 roads with median guardrail. 5. Urban speed management; speed-reducing measures in towns. 6. Increased seat belt wearing by car drivers. 7. Increased seat belt wearing by car passengers. 8. Increased use of child restraints. 9. Increase in share of cars that have airbags. 10. Enhanced neck injury and side impact protection in cars. 11. Increased and more effective police enforcement. 3.1. Reduction of travel pedestrian, cyclist and moped travel

For all these cases except case number 5, estimates were developed of their effects on road safety in Sweden. No specific road safety measure developed as a result of studies conducted by means of the VTI driving simulator was identified; quantifying the effects of research by means of the simulator in terms of fatalities and injuries prevented was therefore not possible.

National travel behaviour surveys made in Sweden during 1984–1985 (Thulin, 1987), 1992–1995 (Thulin and Kronberg, 1998) and 1997–1999 (Nilsson, 2004) show that pedestrian, cycle and moped travel has been reduced. The effects of these reductions were estimated by assuming that the injury and fatality rates remained unchanged, i.e. it was assumed that the number of injuries and fatalities would decline in proportion to the reduction in the amount of travel.

3. Evaluating the effects of selected factors that have influenced long-term trends in road safety in Sweden

3.2. Reduction of travel performed by young drivers

Fig. 1 shows the annual number of road accident fatalities in Sweden from 1970 to 2005. In 1970, 1307 people died in road accidents. In 2005 the number was 440, a reduction of about 66%. A trend line has been included which shows an annual decrease in the number of fatalities of 2.9%. A 95% confidence interval around this trend line is also shown. The trend line shows the systematic improvements in road safety from a fitted value of 1258 fatalities in 1970 to 454 in 2005. In order to identify the contributions of the selected cases of road safety research to reducing the number of road accident fatalities and injuries in Sweden, an attempt was made to estimate the effects on long-term trends of as many factors as possible. The estimates relied to a major extent on previous estimates developed by VTI (Nilsson et al., 2002). Given the fact that the number of road

Between 1989 and 1996, travel performed by drivers aged 18–24 years was reduced from 7758 to 4689 million km (Brüde, 2005). It has remained stable since 1996. The number of killed car occupants aged 18–24 years declined from 141 in 1989 to 77 in 2001, having reached a low of 47 in 1996 and 1997. If the 1989-fatality rate had remained unchanged, 84 fatalities would have been expected to occur in 1996 and each of the years thereafter. 3.3. Construction of motorways (freeways) According to Nilsson et al. (2002) the proportion of vehicle kilometres driven on motorways increased from 18.9% to 22.5% of the total vehicle kilometres on national roads in the period from 1994 to 2000. It was estimated that the increase in the proportion of

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traffic on motorways between 1994 and 2000 reduced the number of fatalities by 10. This estimate was extrapolated to obtain the effects of the increase in the length of motorways between 1970 and 2005.

injury is reduced by 60% (Durbin et al., 2005; Lennon et al., 2008), and the risk of a slight injury reduced by 40% (Lennon et al., 2008).

3.4. Construction of 2 + 1 roads with median guardrail

Nilsson et al. (2002) estimated that increased market penetration of airbags between 1995 and 2001 reduced the number of car occupant fatalities by 25. It was assumed that airbags reduce the risk of fatal or serious injury to front seat car occupants by 20%. The proportion of vehicle kilometres driven by cars equipped with airbags increased from 15% to 60% in this period. For 2005, it is assumed that 90% of vehicle kilometres are made up of cars that have airbags. Effects were estimated by extrapolating from the estimate of Nilsson et al.

The 2 + 1 road is a new concept, developed in Sweden. These are undivided roads that are wide enough to accommodate three lanes. A wire guardrail is installed to prevent or reduce the severity of head-on-crashes. At the end of 2005 there were 1190 km of 2 + 1 roads with median guardrail in Sweden (Carlsson and Brüde, 2005). Carlsson and Brüde (2005) estimated the effects of median guardrails and their estimates were applied. 3.5. Urban speed management The effects of urban speed management were estimated by comparing long-term trends in the number of killed or injured road users between urban and rural areas. There has been a greater decline in the number of fatalities and injuries in urban areas than in rural areas; part of this greater decline can be attributed to speed management measures in urban areas. Nilsson et al. (2002) estimated that new roundabouts constructed between 1990 and 2000 had reduced the number of fatalities by 20. Effects of urban speed management were estimated by extrapolating this estimate to the period from 1970 to 2005 (Vadeby and Brüde, 2006). Roundabouts are used as an indicator of measures taken to manage speed in urban areas. Precise records of other measures, like humps, are not kept. 3.6. Increased seat belt wearing by car drivers Nilsson et al. (2002) estimated that increased seat belt wearing in the period 1994–2001 reduced the annual number of fatalities by almost 11. It was assumed that seat belt wearing by car drivers increased from 15% in 1970 to 92% in 2005. Drivers who do not wear seat belts are involved in accidents more often than drivers who wear seat belts (Evans, 2004). Based on the information given by Krafft et al. (2006), it can be estimated that drivers who did not wear seat belts in 2004 were involved in fatal accidents three times more often than drivers who wore seat belts. Furthermore, it was assumed that seat belts reduce the driver’s risk of fatal injury by 50%. The effects of increased seat belt wearing from 1970 to 2005 were estimated by relying on these assumptions. 3.7. Increased seat belt wearing by car passengers The model used to estimate the effects of increased seat belt wearing among car passengers is analogous to that used for car drivers. It was assumed that wearing a seat belt reduces passenger fatality risk by 30%. Given the selective recruitment of seat belt wearers with respect to accident involvement rate, it was estimated that increased seat belt wearing by car passengers from 1970 to 2005 contributed to reducing passenger fatalities by 15%. 3.8. Increased use of child restraints Child car passenger fatalities in Sweden declined from about 16 in 1970 to less than 5 per year after 1970. Nearly all children of the age 0–3 years who travel in cars in Sweden today are restrained (Anund et al., 2003). Hence, the current number of fatally injured children in cars reflects a situation in which nearly all children are restrained. Estimates of the effects of child restraints have been developed by assuming that the risk of a fatal injury is reduced by 80% for restrained children (Lennon et al., 2008), the risk of a serious

3.9. Increase in share of cars that have airbags

3.10. Enhanced neck injury and side impact protection in cars In Eriksen et al. (2004), it was estimated that increased market penetration of cars that have enhanced neck injury and side impact protection has reduced fatalities by 10, serious injuries by 138 and slight injuries by 250. These estimates were applied. 3.11. Increased and more effective police enforcement From 1981 to 2004 the number of drivers checked by the police in Sweden increased substantially (Brüde, 2005). The number of drivers checked per million vehicle kilometres of travel is a measure of the risk of detection of traffic offences. Effects were estimated based on the relationship between the number of drivers checked and the number of fatalities between 1981 and 2004. These are crude estimates, as they do not control for any confounding factor, but rely on the simple bivariate relationship between the number of drivers checked and the number of fatalities. 3.12. Total effects of all factors Table 1 summarises the estimated contributions of the factors included to reducing traffic fatalities and injuries in Sweden from 1970 to 2005. All these estimates are “ballpark estimates”, i.e. rough estimates indicating order of magnitude only. Moreover, not all factors that may have contributed to reducing the number of fatalities are included. Factors not included are, for example, a gradual shift towards a more experienced population of drivers (i.e. the average driver is more experienced today than the average driver was in 1970), a number of highway improvements (road lighting, guardrails, other minor improvements) and more subtle changes in safety culture not easily measured. Each of the estimates of safety effect listed in Table 1 represents the so-called “first-order” effect of a factor. The first-order effect is the effect of a factor provided it is the only factor that has an effect and everything else remains unchanged. When estimating the combined effects of the factors, first-order effects have to be adjusted for double counting, since all factors influence the same group. Thus, if for example, more effective police enforcement has reduced the number of fatalities by 150, the other factors can only have an effect on the fatalities remaining after these 150 have been subtracted. Combined effects adjusting for double counting were estimated by assuming that first-order effects are independent of each other, i.e. the first-order effect attributed to a specific factor does not change if another factor is introduced. 3.13. Assessing the contribution of research to the factors To what extent are these factors based on research, more specifically on the cases that were selected for detailed analysis in this study? An assessment appears in Table 1. The assessment is crude

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Table 1 Estimated effects of selected road safety measures and other factors and appraisal of the extent to which the factors are based on research. Factors contributing to reducing the number of fatalities

Estimated first-order impact of factor in reducing the number of Fatalities

Reduction of walking, cycling and motorcycle riding Reduction of young driver exposure Construction of motorways Construction of median guard rails on undivided roads Urban safety management; speed reduction in towns Increased seat belt wearing Increased use of child restraints in cars Increased market penetration of cars with airbags Improved side impact and neck injury protection More effective police enforcement Sum of first-order effects Total effects adjusted for double counting

Serious injury

Period during which effect accumulated

Possible contributing of research to the effect of the factor

Slight injury

50

590

1000

1985–2005

None

55 30 30

500 120 120

950 0 −100

1990–1994 1970–2005 1998–2005

None Small Large

40

255

590

1976–2005

Medium

150 8 50

300 100 24

310 100 110

1970–2005 1970–2005 1990–2005

Small Large Small

10

138

250

1996–2005

Large

150

250

220

1981–2005

Medium

573 453

2737 2035

3430 3230

and not based on very precise criteria. The importance of research in contributing to the various safety measures was judged by answering two questions: 1. Did research lead to the development of a road safety measure that would otherwise not have been developed? 2. What was the contribution of Swedish research to the development of research-based road safety measures? Research was judged to have made a major contribution to child restraints, enhanced neck injury protection, side impact protection and 2 + 1 roads with median guardrails. All these safety measures are to a very great extent based on Swedish research. Enhanced neck injury protection and 2 + 1 roads are Swedish inventions. Swedish research was judged to have made some contribution to urban speed management and more effective police enforcement, but for both measures there is abundant international research. The contribution of Swedish research was rated as small with respect to seat belts, airbags and motorways. The decline in travel performed by pedestrians, cyclists, motorcyclists and young car drivers was judged not to be related to research. 4. Cost–benefit analyses Cost–benefit analyses have been made for the road safety measures covered by four of the five case studies. No cost–benefit analysis was made for the VTI driving simulator. The cost–benefit analyses were based on the estimated safety effects, as well as estimates of the costs of safety measures that were introduced as a result of the research performed in the four cases included. The costs of research were also included. Official Swedish values were used for the monetary valuation of the prevention of fatalities and injuries (SIKA, 2005). In addition to fatalities prevented, the cost–benefit analyses also included estimates of the number of injuries prevented. The prevention of a fatality was valued at SEK 17,511,000 (D 1,870,000), the prevention of a serious injury at SEK 3,124,000 (334,000D ) and the prevention of a slight injury at SEK 175,000 (18,700D ). For urban speed management, increased travel time was included for about 20% of all vehicle kilometres driven in urban areas. A value of travel time of 42 SEK (4.5D ) per person per hour was applied. Car occupancy was assumed to be 1.7 persons. A discount rate of 4% per year was used. Public outlays were multiplied by a factor of 1.53 to obtain their social opportunity cost.

The analyses took the estimated effects of the measures in the year 2005 as the basis for estimating costs and benefits. No attempt was made to reconstruct the historical development of costs and benefits in past years. The analyses adopted a forward looking perspective to estimate the present value of benefits assuming that these last 20 years for urban safety management, 15 years for vehicle safety features, 3 years for child restraints and 1 year for police enforcement. 4.1. Urban speed management The monetary value of the safety benefits of urban speed management were estimated as follows:



(32 × 17, 511, 000)+

 190 0.59

  556

× 3, 124, 000 +

0.32



× 175, 000

× 13.59 = 25387.4 million SEK

The terms in brackets are the effects on fatalities, serious injuries and slight injuries, adjusted for double counting. The division by 0.59 for serious injuries and 0.32 for slight injuries is an adjustment for incomplete reporting of injuries in official accident statistics. 13.59 is the present value factor for a period of 20 years employing an annual discount rate of 4% and assuming that benefits do not change in these 20 years. Urban speed management is likely to lead to increased travel time, at least for some of the traffic in urban areas. It was assumed that travel time has increased on access roads in urban areas, which carry about 20% of all traffic in urban areas. Applying the monetary valuation of travel time stated above, the value of increased travel time was estimated as 10781.4 million SEK. Subtracting the added costs of travel time from the safety benefits produces an overall benefit of 25387.4 − 10781.4 = 14606.0 million SEK. According to information provided in the main report of the project (Kolbenstvedt et al., 2007), the costs of research and development for urban speed management were about 15 million SEK. It was assumed that the cost of implementing measures can be represented by the costs of constructing all roundabouts that existed in Sweden at the end of 2005 (1500). The mean cost of constructing a roundabout is about 3 million SEK (Brüde and Larsson, 1985). Costs of road maintenance were assumed to increase by 1% of the investment cost. Costs were estimated as 7820.7 million SEK. The benefit–cost ratio becomes: 14606.0/7835.7 = 1.86.

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Table 2 Cost–benefit analysis of cases selected for detailed study. Measure

Fatalities prevented (adjusted for double counting)

Present value of benefits (million SEK)a

Costs of research and development (million SEK)

Urban speed management Child restraints in cars Neck injury protection Side impact protection Police enforcement

32 6 0 8 119

14606.0 711.0 1499.6 4840.2 3181.3

15.0 10.0 100.0 10.0 30.0

7820.7 210.0 100.0 1300.0 765.0

1.86 3.23 7.50 3.69 4.00

24838.1

165.0

10195.7

2.40

All measures a

Benefit–cost ratio

1 SEK = 0.107D in April 2007.

4.2. Child restraints in cars Increased use of child restraints in cars were estimated to prevent 6 fatalities, 18 serious injuries and 104 slight injuries in 2005, all adjusted for double counting. Benefits were estimated as 711 million SEK. According to the main report (Kolbenstvedt et al., 2007), the costs of research and development were about 10 million SEK. 60,000 child seats are sold every year at a mean price of 3500 SEK per seat. This gives a cost of 210 million SEK per year (a one-time expenditure). The benefit–cost ratio becomes: 711.0/220.0 = 3.23. 4.3. Side impact protection Side impact protection comprises side airbags that have been developed by Autoliv and subsequently became standard equipment in Volvo and Saab cars and later on in other makes and models. Effects in 2005, adjusted for double counting, were estimated as a fatality reduction of 8 and a reduction of serious injuries of 56. This gives a benefit of



Costs of implementing measure (million SEK)

(8 × 17, 511, 000) +

 56

0.59



× 3, 124, 000

× 11.118

= 4840.2 million SEK According to the main report (Kolbenstvedt et al., 2007), 1.3 million cars in Sweden had side impact protection in 2005. The added cost per car is 1000 SEK. Total cost becomes 1300 million SEK. The costs of research and development cannot be estimated very precisely, as part of it was done by the car industry and car manufacturers are reluctant to publish information about their costs for research and development. However, a rough estimate was obtained for research and development for neck injury protection and side impact protection put together. The costs were allocated between these two safety features. Costs of research and development were estimated as 10 million SEK. Total costs thus become 1310 million SEK. The benefit–cost ratio is: 4840.2/1310.0 = 3.69. 4.4. Neck injury protection Effects, adjusted for double counting, have been estimated as a reduction of 47 serious injuries and 235 slight injuries. In contrast to the other safety measures, these estimates have been adjusted for incomplete accident reporting. There is no effect on fatalities. Benefits become [(47×3, 124, 000)+(235×175, 000)]×11.118 = 1499.6 million SEK Terms in brackets represent the benefits; 11.118 is the present value factor for 15 years using a discount rate of 4% per year. Costs of research and development have been estimated as 100 million SEK (Kolbenstvedt et al., 2007). By 2005, it was estimated (Kolbenstvedt et al., 2007) that slightly less than 350,000 cars in Sweden have enhanced neck injury protection at a cost of

300 SEK per car. The cost of installing enhanced neck injury protection is 100 million SEK. Total costs become 200 million SEK. The benefit–cost ratio can be estimated as: 1499.6/200.0 = 7.50. 4.5. Increased and more effective police enforcement It was estimated that increased and more effective police enforcement reduce fatalities by 119, serious injuries by 186 and slight injuries by 207, all adjusted for double counting. Benefits were estimated as



 186

(119 × 17, 511, 000)+

0.59

  207

× 3, 124, 000 +

0.32



× 175, 000

= 3181.3 million SEK Effects are assumed to last for one year only; hence, no present value factor is included. Based on a previous study (Elvik and Amundsen, 2000), costs are estimated as 500 million SEK per year. When the social opportunity cost of public expenditures is added, this becomes 765 million SEK. The costs of research have been estimated as 30 million SEK (Kolbenstvedt et al., 2007). Total costs are 795 million SEK. Benefit–cost ratio becomes: 3181.3/795.0 = 4.00. Table 2 presents the results of the analyses. As can be seen from Table 2, benefits exceed costs by a wide margin for all safety measures. In other words, investment in research in these areas has resulted in the introduction of road safety measures whose benefits greatly exceed the costs of these measures. 5. Discussion The study presented in this paper was given the mandate of producing an estimate of the benefits to society of road safety research funded by the Swedish Transport Research Council and VINNOVA during the period 1971–2004. This task is almost impossible to fulfil, since there is no way of knowing how road safety in Sweden would have developed if the research had not taken place. The case study design adopted does not satisfy the most basic condition for causal inference, that of describing counterfactual changes (i.e. what would have happened if research had not taken place). This condition is best fulfilled in experimental study designs, in which the control group serves to establish the counterfactual. No control group was available for this study. We are therefore not in a position to claim that we have shown that road safety measures based on research have caused the observed decline in road accident fatalities in Sweden after 1970. The effects estimated for the research-based road safety measures account for less than half the observed decline in road accident fatalities in Sweden since 1970, suggesting that other factors have been more important. The percentage reduction in road accident fatalities in Sweden since 1970 is greater than the corresponding reductions in Denmark, Finland, Norway, Great Britain, Australia and the United States of America. The Netherlands is the only highly motorised country comparable to Sweden that has accomplished a greater percentage reduction of fatalities than Sweden.

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The study has several limitations. It selected just a few research projects for detailed examination. Surely some of the very many projects not studied in detail were unsuccessful. Besides, the Swedish Transport Research Council was not the only public body funding road safety research in Sweden. Research funded by other agencies is possibly of equal importance for changes in road safety. The analysis of benefits is crude and the estimated effects of the safety measures may seem implausibly large. Nevertheless, it is highly likely that various road safety measures have contributed to a major part of the reduction in road accident fatalities in Sweden, as well as in other countries that have experienced similar changes. Despite the uncertainty of any estimate of the contribution of a specific road safety measure, the main finding of the study is robust. If the safety effects attributed to urban speed management and police enforcement are cut by half – the rationale being that these measures are based as much on foreign research as on Swedish research – benefits remain greater than costs (10,614 million SEK benefit; 10,361 million SEK costs). The Transport Research Council funded research amounting to almost 450 million SEK during the years 1973–2004 (data for 1971 and 1972 are missing). Part of the 450 million were for the projects used as cases in this study, but even if all the remaining research was unsuccessful, producing no benefits in terms of fewer fatalities or injuries, costs still would marginally exceed benefits (10,361 million SEK + 350 million SEK = 10,711 million SEK). It is unlikely that all this research was unsuccessful. 6. Conclusions Road safety research funded by VINNOVA and its predecessor, the Swedish Transport Research Council, during the period 1971–2004 has resulted in the development and implementation of some road safety measures that have contributed importantly to the decline in road accident fatalities in Sweden between 1970 and 2005. The benefits of these measures exceed their costs by a wide margin. Acknowledgement This study was funded by Verket för Innovationssystem (VINNOVA). References Aldman, B., 1962. Biodynamic studies on impact protection. Thesis. Acta Physiol. Scand. 56 (Suppl. 192). Anund, A., Falkmer, T., Forsman, Å., Gustafsson, S., Matstoms, Y., Sörensen, G., Turbell, T., Wenäll, J., 2003. Child Safety in Cars—Literature Review. VTI Report 489A. Swedish Road and Transport Research Institute, Linköping. Braver, E.R., Kyrychenko, S.Y., 2003. Efficiency of Side Airbags in Reducing Driver Deaths in Driver-Side Collisions. Insurance Institute for Highway Safety Arlington. Brüde, U., 2005. Basstatistik over olyckor och trafik samt andra bakgrundsvariabler. Version 2005-06-30. VTI-notat 27-2005. Väg- och transportforskningsinstitutet, Linköping.

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