Rune Elvik

..Speed and speeding is used as an example of a road safety problem to illustrate how the various dimensions can be measured...

..The exponential functions fitted the data extremely well and imply that the effect on accidents of a given relative change in speed is largest when initial speed is highest...

..The main finding, however, is that the current level of enforcement is too low. Cost-benefit analyses show that substantially increasing the amount of police enforcement is cost-effective...

..Traffic speed strongly influences impact speed in crashes and therefore has major implications for public health...

..The technique is illustrated by means of numerical examples...

..e. techniques other than the empirical Bayes approach) for controlling for confounding factors were tested. The techniques were found not to produce unbiased estimates of effect and their use is therefore discouraged...

..This shows that the high injury rate for pedestrians and cyclists in the current transport system does not necessarily imply that encouraging walking or cycling rather than driving will lead to more accidents...

....

..Smaller prediction errors were associated with predictions based on accident prediction models than predictions not based on such models...

..Steps that can be taken to bring practice closer to the state-of-the-art are outlined...

..A study of the effects of a road safety programme implemented in Victoria, Australia between 1990 and 1996 indicated that the effects of safety measures are weakened when these measures are combined with other road safety measures...

..The chief lesson is that past trends do not provide a reliable basis for predicting future developments with respect to the number of traffic fatalities...

..The characteristics that can make a problem difficult to solve are to some extent present for all the five problems shown to be persistent in this paper...

..It is concluded that at the current state of knowledge, it is not possible to meaningfully estimate the total uncertainty inherent in road safety programmes. The prospects of reducing uncertainty by means of research are discussed...

..The criteria of causality are indicative only and cannot provide a basis for stringent logical proof of causality...

..The re-analysis shows smaller safety benefits associated with the use of bicycle helmets than the original study...

..Examples are given of how all these items may influence the findings of a single study or make synthesising findings from multiple studies difficult. A checklist for assessing study quality is provided...

..It is therefore by no means certain that the objective of reducing fatalities and serious injuries by 50% will be realised...

..On the whole, the research that has been reported so far regarding road safety effects of porous asphalt is inconclusive. The studies are not of high quality and the findings are inconsistent...

....

..The experience so far suggests that deregulation of railways is associated with improved rail safety. This association does, however, not necessarily imply a causal relationship...

..It is hoped that proposing a few basic mechanisms that can summarise the impact of a number of risk factors will stimulate research that may lead to a more general theory of accident causation...

..All cost-effective measures can be funded within current budgets, provided the use of inefficient measures ceases...

..During the years 1995-2004, the rates for fixed penalties for traffic offences in Norway increased substantially. This paper evaluates the effects on compliance of these increases...

..Lack of control for confounding factors remains the most serious threat to the validity of road safety evaluation studies...

..These effects almost cancel each other, leading to a very small net change in the expected number of accidents...

..These car owners might have had a higher accident rate than other car owners irrespective of the technical condition of the car...

..These results are not statistically significant and highly uncertain. The study clearly illustrates many of the difficulties often encountered in non-experimental accident research...

..At the current state of knowledge, a more stringent evaluation of the extent to which theory can explain the findings of road safety evaluation studies is, in most cases, not possible...

..Total annual bicycle injury costs are huge, but these costs must be balanced against the benefits of bicycling, related to health and environment. Accident reporting and data should be enhanced to enable a reduction of bicycle injuries...

..It is important to assess the extent to which current value-of-life estimates depend on study methods and social context...

..Simple before-and-after studies, not controlling for any confounding factors should never be trusted and are likely to overstate the effects of road safety measures...