Evaluating the benefits of road safety research The case of Sweden Rune Elvik, Marika Kolbenstvedt, Beate Elvebakk, Arild Hervik, Lasse Bræin 31.10.20...
Evaluating the benefits of road safety research The case of Sweden Rune Elvik, Marika Kolbenstvedt, Beate Elvebakk, Arild Hervik, Lasse Bræin 31.10.2007
Mission impossible? § Main research problem: § 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? § Issues arising: § Can this question be answered at all by means of research? § Which study design is best suited to the task of identifying and preferably quantifying the benefits of road safety research? § How can the output of road safety research be identified in terms of the effects it is likely to produce? 31.10.2007
Alternative research designs § Before-and-after study § No clearly defined before- and after-periods; difficult to control for confounding factors
§ Time-series analysis § No distinct intervention points or sudden jumps in series; effects of research difficult to detect
§ Comparison of Sweden to other countries § Other countries have also performed road safety research
§ Multivariate econometric modelling § Too few data points and too many variables; insufficient variation in research effort for effects to be detected
Possible effects of road safety research § Although road safety research is an applied field, its effects on road safety are multiple and almost always indirect § A rough typology of impacts: § The development or invention of new road safety measures § The evaluation of the effects of road safety measures not developed by means of research exclusively § Developing new concepts and ideas; new perspectives for understanding road safety (Vision Zero) § Developing new research methods and techniques for analysis § Finding out things that are ”nice to know”, but have no immediate application 31.10.2007
The case study approach § Criteria for selecting cases: § Cases represent high-quality research ? published in scientific journals § Case histories can be reconstructed in sufficient detail to describe the causal chain: research ? road safety measure ? effects of road safety measure ? changes in road safety in Sweden § Case histories should represent the breadth of research and multiple institutions
§ Possible objections: § Only success stories are likely to be identified § The sample of cases will be very incomplete and represent only a small share of research 31.10.2007
Cases selected § Urban safety management, illustrated by the Växjö-project (Lund Institute of Technology) § Child restraints, the ISOFIX-system (Chalmers Technical University and Swedish Road and Transport Research Institute - VTI) § Development of neck injury protection and side-impact protection (Chalmers, Volvo, Saab, Autoliv) § Police enforcement (Uppsala University and Swedish Road and Transport Research Institute) § Research conducted by means of VTI’s driving simulator 31.10.2007
Reconstruction of case history (chronology) Critical review of published reports and scientific papers Interviews with researchers and funding agencies Assessment of first order benefits § Effects on safety § Extent of application
§ Assessment of costs § Cost-benefit analysis (did not include VTI’s driving simulator) § Assessment of total impacts on road safety in Sweden 31.10.2007
An example of a case study § Roundabouts and other speed-reducing measures were introduced in Växjö § The trial was controversial and attracted great publicity § Effects were evaluated and published in a scientific journal (Accident Analysis and Prevention, 2000, 11-23) § The use of roundabouts in Sweden as a whole is used as an indicator of speed control measures taken in urabn areas § Effects in macro are estimated
First order effects of urban speed management § Reduction in number of fatalities: § Reduction in number of serious injuries: § Reduction in number of slight injuries:
40 170 180
§ Similar estimates were developed for the other cases as well as for other measures that may have influenced road safety in Sweden from 1970 to 2005
Discussion and conclusions § Methodological limitations: § There was no comparison group ? causality cannot be established as we cannot know the counterfactual (”what would have happened without the research”) § Only a few cases were selected; these may have been more successful than many other research projects § Estimates of costs and benefits are very crude and amount to little more than educated guesses
§ Conclusions are likely to be robust: § Benefits are considerably higher than costs; even if they are overestimated by a factor of about 2-4 conclusions remain the same § Sweden has improved road safety more than many other countries 31.10.2007
