An experiment on rider stability while mounting: Comparing middle-aged and elderly cyclists on pedelecs and conventional bicycles.

Pedelecs, popular among elderly cyclists, are associated with a higher injury risk than conventional bicycles. About 17% of these injuries are due to falls while (dis)mounting. Using instrumented bicycles, this study aimed to identify factors contributing to the stability of self-chosen mounting methods in four user groups: 30-45 versus 65+ years of age and males versus females. Mounting stability on pedelecs was compared with that on conventional bicycles, in controlled experimental setting (task in a fenced off parking lot) but also in real traffic conditions (traffic light turns green). Two mounting phases were differentiated: phase 1 as the transition from 'earth bound' to 'balance' and phase 2 as the acceleration to achieve harmonized cycling. Stability was operationalised in terms of the duration of these phases: the shorter their duration, the higher the stability. Pedelecs were shown to be less stable in phase 1 than conventional bicycles, irrespective of user group. For all user groups, only in phase 2 the advantages of electrical support kicked in. Results obtained in traffic conditions confirmed the patterns obtained in the controlled setting, with as only difference a lower speed in traffic conditions, which held for both mounting phases and bicycle types. Also measures of physical limitations due to low muscle strength were shown only to be compensated for by pedal support in phase 2 and not in phase 1. Further, mounting characteristics affected pedelec stability in phase 1 and not in phase 2. Higher stability was associated with a) starting while seated and b) using the pedal to push off. Although, these mounting characteristics were confounded with age, gender, and muscle strength, the pattern of results still suggest certain mounting techniques to be more beneficial for pedelecs. The results further illustrate the importance of a deeper understanding of the interactions of bicycle types and user groups on critical manoeuvres and their potential contribution to the optimisation of pedelec design and the training of safe mounting techniques.

Effect of physical effort on mental workload of cyclists in real traffic in relation to age and use of pedelecs.

To improve cycling safety, insight is required into the factors that contribute to road safety of older cyclists. From the wide range of possible factors, this paper addresses the role of physical effort on mental workload of cyclists with the aim to investigate whether physical effort affects mental workload of cyclists in real traffic in a field experiment. Two instrumented bicycles, a conventional bicycle and a pedelec, were used. Mental workload of cyclists in two age groups - 30-45 years and 65 years and over - was measured by means of a secondary cognitive task requiring the detection and reaction to visual stimuli on a cycle route that varied in physical effort and task complexity. We expected physical effort to impair performance on the secondary task in complex traffic sections and not in simple sections, and that this impairment would be greater for older cyclists because of age related reduced muscle strength than for younger cyclists. We expected this impairment to be smaller if a pedelec was used. If such would be the case, this would indicate pedelecs to be beneficial for this older age group, because of a lower mental workload. Our study confirmed that increased physical effort in complex traffic sections deteriorated the detection of relevant stimuli in both age groups. Overall, older cyclists had longer reaction times and lower hit rates than younger cyclists. Mental workloads of cyclists are basically the same when cycling on a conventional bicycle or on a pedelec. In theory, pedelecs may be beneficial to reduce physical effort in cycling in order to maintain enough mental capacity to handle complex traffic situations. However, this study did not demonstrate these benefits. As pedelecs are often used for longer trips, by elderly with low muscle strength, future studies should also explore the effect of higher physical effort over longer periods of time, and also specifically in elderly with low muscle strength.

An epidemiological study of the risk of cycling in the dark: the role of visual perception, conspicuity and alcohol use.

To curtail the rising numbers of cyclists seriously injured in road crashes, more insights are needed into the factors that contribute to these crashes. For instance, darkness is known to be associated with higher injury rates, but little is known about the relative influence of factors such as poor conspicuity, impaired perception and alcohol use among cyclists. To examine these factors, the present study analyzed the epidemiological crash data for three meteorological light conditions: daylight, late evening darkness and early morning darkness; for two crash types: crashes with (M-crashes) and without motorized traffic (NM-crashes); and for different age groups. The relative injury rates (injury risk per distance travelled in darkness corrected for daylight injury risks for each age group) confirmed findings from earlier studies that cycling in late evening darkness is associated with higher injury rates than cycling in daylight conditions. This is the case for both crash types with only small differences between the age groups suggesting that poor conspicuity (M-crashes) and impaired perception (NM-crashes) may play a role. In comparison to late evening darkness, relative injury rates in early morning darkness are much higher. This is the case for both crash types with large differences among the age groups, suggesting that in addition to the absence of daylight also age related risk factors are at play. Support for this hypothesis was found from the analyses of hospital records, showing that the proportion of seriously injured cyclists who have been drinking is highest in early morning darkness and has strongly increased over the last decades. These insights provide input for the selection of countermeasures such as improved lighting (both street and bicycle lights) and interventions targeting alcohol use among cyclists.

Studying the role of vision in cycling: critique on restricting research to fixation behaviour.

In a recent study published in Accident Analysis & Prevention, Vansteenkiste et al. (2013)--as one of the first in this field--investigated the visual control of bicycle steering. They undertook the interesting task of testing cyclists' eye fixation behaviour against Donges' two-level model of steering, i.e. the guidance level to anticipate alternations in the course of the road and the stabilization level for lane keeping. Although the laboratory experiment itself is well conducted, we believe that its results cannot be used to test the two-level model of steering as developed for driving. The test track was only 15m long, was completely straight and was known in advance. Accordingly, it did not provide adequate conditions for testing the guidance level. Furthermore, as the experimental lanes were much narrower than real-world cycling lanes, the stabilization level differed considerably from that in the real world. The study by Vansteenkiste et al. (2013) may provide valuable insight into the role of vision in 'precision steering', but, as we discuss in the paper, more elaborate research paradigms are needed to achieve more comprehensive knowledge of the role of vision in real-world cycling and cycling safety.

Do young novice drivers overestimate their driving skills more than experienced drivers? Different methods lead to different conclusions.

In this study we argue that drivers have to make an assessment of their own driving skills, in order to sufficiently adapt to their task demands in traffic. There are indications that drivers in general, but novice drivers in particular, overestimate their driving skills. However, study results differ on the subject of self-assessment of skills. The objectives of this paper are (1) to study whether novice drivers indeed overestimate their driving skills more than experienced drivers; and (2) to evaluate the influence of the method to measure self-assessment of skills (i.e. comparison to 'average' and 'peer' driver versus independent measures of own performance). The results show that the conclusion of whether novice drivers overestimate their driving skills is highly affected by the method chosen to measure self-assessment of skills. When drivers are asked to compare themselves to the average and peer driver, we can conclude that novice drivers are not as optimistic about their driving skills as has been reported in the past. They seem to recognize that they are not as skilled (yet) as the average driver. However, when comparing their self-assessment with their actual behaviour there are indications that they overestimate their driving skills.