Gender differences in accident risk with e-bikes-Survey data from Norway.

E-bikes are becoming increasingly popular, and are given an important role in the green mobility of the future. However, some have raised concerns that the increased speed and the increased weight of the e-bike can lead to more accidents among cyclists riding an e-bike, as compared to conventional bicycles. Furthermore, it has been suggested that e-bikes may appeal to new groups of cyclists with little cycling experience, which may further impede cyclist safety. Previous research has not provided a clear picture. We investigate these questions with data from three surveys carried out in Norway (N = 7752). A logistic regression analysis comparing conventional and electric bicycles, controlling for age gender and exposure, shows an overall risk increase (all accidents) for e-bike users. The results suggest that this increased risk derives from females having a higher accident risk on e-bikes. For men there is no risk difference between e-bikes and conventional bikes. Some, but not all, of this elevated risk can be attributed to being unfamiliar with the bicycle. E-bikes are not more likely to cause serious accidents than conventional bicycles. In-depth analysis of accident causation showed that there was no difference in the factors leading to accidents, except that there was a somewhat higher prevalence of accidents resulting from balance problems with e-bikes.

Safety in numbers for cyclists-conclusions from a multidisciplinary study of seasonal change in interplay and conflicts.

In many European countries, it is a political goal that future growth in local travel should be absorbed by sustainable transport modes. Concerns that increased walking and cycling produce more accidents have been countered by the "safety in numbers" (SiN) argument. According to SiN, the more walkers/cyclists there are in a population, the lower their risk. SiN has been demonstrated in cross sectional and longitudinal studies, but the mechanisms behind the effect have yet to be proven. Previous studies have mostly relied on register data. The current study, carried out in 2013 and 2014 tests the existence of this effect in a more controlled manner. This is achieved through the use of three data sets: (1) roadside survey data with cyclists, pedestrians and car drivers from Oslo carried out at three time points in the cycling season (2) a panel study covering the same time period, and (3) video observations at four different locations in Oslo. By exploiting the natural seasonal variation in cycling frequency, and by using a repeated measures design we can further control for other factors suggested to lie behind the SiN mechanism, such as differences in infrastructure and traffic culture. The results suggest that bicyclists experience a short term Safety in Numbers effect through the season. Each individual cyclist experiences fewer occasions of being overlooked by cars and fewer safety critical situations (near-misses). Video observation data confirm this pattern. However, the SiN effect seems to be countered by another mechanism taking place at the same time: the influx of inexperienced and risk-taking cyclists through the season. Thus car drivers and pedestrians also report to find themselves being surprised by cyclists in traffic late in the season.

Risk compensation--the case of road lighting.

The hypothesis of this article is that drivers will not adjust their behavior, i.e. drivers are not expected to increase their speed, reduce their concentration or travel more when road lighting is installed. The hypothesis was based on previous research showing that road lighting reduces road accidents and that average driving speeds do not increase when road lighting is installed. Our results show that drivers do compensate for road lighting in terms of increased speed and reduced concentration. Consequently, the hypothesis is rejected. This means that road lighting could have a somewhat larger accident-reducing effect, if compensation could be avoided. The fact that previous research has found no change in average speed when road lighting is introduced, seems to be explained by increased driving speeds by some drivers being counterbalanced by a larger proportion of more slowly driving groups of drivers (elderly people and women), i.e. different subgroups of road users compensate in different ways.

Can road traffic law enforcement permanently reduce the number of accidents?

In this paper it is argued that conventional analyses of road user adaptation to traffic law enforcement, based on parametric rational-choice theory, are flawed. Such analyses only consider road-user actions as a response to enforcement level and penalty size and do not simultaneously consider enforcement as a response to road-user behaviour. If each party is considered a rational agent who adapts to the other's behaviour, the proper way to analyze the outcomes is by the way of game theory. A game-theoretic model is presented and the main implications are: (i) most attempts at enforcing road traffic legislation will not have any lasting effects, either on road-user behaviour or on accidents; (ii) imposing stricter penalties (in the form of higher fines or longer prison sentences) will not affect road-user behaviour; (iii) imposing stricter penalties will reduce the level of enforcement; (iv) implementing automatic traffic surveillance techniques and/or allocating enforcement resources according to a chance mechanism, and not according to police estimates of violation probability, can make enforcement effects last, but both alternatives are difficult to implement. Relevant empirical studies are reviewed, and they seem to support the conclusions arrived at by the game-theoretic model.