Investigating cycling kinematics and braking maneuvers in the real world: e-bikes make cyclists move faster,brake harder,and experience new conflicts

Pedelecs (e-bikes), which facilitate higher speeds with less effort in comparison to traditional bicycles (t-bikes), have grown considerably in popularity in recent years. Despite the large expansion of this new transportation mode, little is known about the behavior of e-cyclists, or whether cycling an e-bike increases crash risk and the likelihood of conflicts with other road users, compared to cycling on t-bikes. In order to support the design of safety measures and to maximize the benefits of e-bike use, it is critical to investigate the real-world behavior of riders as a result of switching from t-bikes to e-bikes.Naturalistic studies provide an unequaled method for investigating rider cycling behavior and bicycle kinematics in the real world in which the cyclist regularly experiences traffic conflicts and may need to perform avoidance maneuvers, such as hard braking, to avoid crashing. In this paper we investigate cycling kinematics and braking events from naturalistic data to determine the extent to which cyclist behavior changes as a result of transferring from t-bikes to e-bikes, and whether such change influences cycling safety.Data from the BikeSAFE and E-bikeSAFE naturalistic studies were used in this investigation to evaluate possible changes in the behavior of six cyclists riding t-bikes in the first study and e-bikes in the second one. Individual cyclists’ kinematics were compared between bicycle types. In addition, a total of 5092 braking events were automatically extracted after identification of dynamic triggers. The 286 harshest braking events (136 cases for t-bike and 150 for e-bike) were then validated and coded via video inspection.Results revealed that each of the cyclists rode faster on the e-bike than on the t-bike, increasing his/her average speed by 2.9–5.0 km/h. Riding an e-bike also increased the probability to unexpectedly have to brake hard (odds ratio = 1.72). In addition, the risk of confronting abrupt braking and sharp deceleration were higher when riding an e-bike than when riding a t-bike.Our findings provide evidence that cyclists’ behavior and the way cyclists interact with other road users change when cyclists switch from t-bikes to e-bikes. Because of the higher velocity, when on e-bikes, cyclists appear to have harder time predicting movements within the traffic environment and, as a result, they need to brake abruptly more often to avoid collisions, compared with cycling on t-bikes. This study provides new insights into the potential impact on safety that a cycling society moving to e-bikes may have, indicating that e-cycling requires more reactive maneuvers than does cycling traditional bicycles and suggesting that any distractive activity may be more critical when riding e-bikes compared to traditional bikes.     

Testing extrinsic and intrinsic motivation as explanatory variables for the safety climate–safety performance relationship among long-haul truck drivers

The paper tests the proposition that the organizational climate-behavior relationship is based primarily on extrinsic motivation induced by climate perceptions. Using safety climate as exemplar, the effect of climate-induced extrinsic motivation was compared with that of engagement-induced intrinsic motivation on safety behavior and subsequent injury outcomes. Using a sample of long-haul truck drivers representing lone employees, (individual-level) safety climate perceptions and employee engagement predicted safety behavior, which mediated their effect on subsequently measured road injury outcomes. Consistent with meta-analytic evidence suggesting a non-symmetric compensatory relationship between extrinsic and intrinsic motivation, high safety climate undermined the effect of engagement on safety behavior with the reverse being true under low safety climate. This resulted in a moderation effect of engagement on the strength of relationship between climate perceptions and safety behavior. Theoretical and practical implications for climate, engagement, and lone work research are discussed.     

Developing mixed methods research in sport and exercise psychology: Critical reflections on five points of controversy

ObjectivesTo stimulate debate in sport and exercise psychology about the nature of mixed methods research as currently practiced and how this approach might develop in the future.DesignAn exploration of five points of controversy relating to mixed methods research.MethodA presentation of critical reflections on the following. (1) Mixing methods as a non-debate, (2) Purists, pragmatists and mixing paradigms, (3) Integrating findings and representational forms, (4) Judgment criteria and mixed methods research, and (5) Power, politics and what counts in mixed methods research.ResultsThe examples provided of mixed methods research in action indicate that a number of problematic issues regarding both process and product have been neglected.ConclusionsMixed methods research offers a number of conceptual, practical and pedagogical challenges that need to be addressed if this form of inquiry is to develop its full potential in sport and exercise psychology.     

Personality subtypes of young drivers. Relationship to risk-taking preferences, accident involvement, and response to a traffic safety campaign

The present study aimed at identifying subtypes of young drivers (N=2524) and evaluate how these responded to a traffic safety campaign. On basis of a cluster analysis of personality measures, six subtypes of young drivers were identified. The subtypes were found to differ on self-reported risky driving behaviour, attitudes towards traffic safety, risk perception, estimation of own driving skills, and accident involvement. Two of the subtypes were identified as high-risk groups in traffic. The first high-risk group consisted of mostly men, characterised by low levels of altruism and anxiety, and high levels of sensation-seeking, irresponsibility, and driving related aggression. The second high-risk group reported high sensation seeking, aggression, anxiety, and driving anger. The subtypes were also found to differ on how they evaluated and responded to the traffic safety campaign. The results indicated that the campaign seemed to appeal most to the low-risk subtypes. Gender differences within each subtype were also found on the different traffic related measures, as well as on response to the campaign. It is concluded that young drivers should not be treated as a homogenous group pertaining to road safety. Practical suggestions on how to promote safe driving among these subtypes are also discussed.     

An empirical analysis of the characteristics of drivers who are ticketed for traffic offences

This study uses a unique individual-level dataset that merges Israeli census data with official information on traffic tickets issued over a period of seven years in order to explore the socio-demographic characteristics of drivers who receive traffic tickets. The dataset included 409,051 drivers who received a total of 830,763 traffic tickets. The results indicate that about 60% of drivers received at least one ticket during the study period. However, drivers who received tickets were not distributed evenly in society. Of those with the most tickets, 93% were male, and half were in the youngest group of drivers studied. The effect of socioeconomic status appears to differ across different types of offenses. Implications and suggestions for future research are discussed.     

Gender and age-related differences in attitudes toward traffic laws and traffic violations

The study examined gender and age-related differences in drivers’ normative motives for compliance with traffic laws and in gain–loss considerations related to driving. Two age groups of male and female students, totaling 181 respondents, completed a questionnaire measuring several normative motives for compliance with traffic laws, perceived gains and danger involved in the commission of traffic violations, and the frequency of committing various driving violations. The results show that younger drivers and male drivers express a lower level of normative motivation to comply with traffic laws than do female and older drivers. The lowest level of perceived importance of traffic laws relative to other laws was found among young male drivers. The commission of traffic violations was found to be related more to the evaluation of traffic laws among men and younger drivers, compared to women and older drivers. The perceived danger involved in the commission of a driving violation, however, was found to constitute much more of a factor among women than among men before the commission of traffic violations. Perceived gains involved in the commission of violations were more strongly pronounced among older drivers than among younger drivers. Results are discussed concerning different types of attitude–behavior relationships in the context of driving.     

Auditory localisation of conventional and electric cars: Laboratory results and implications for cycling safety

When driven at low speeds, cars operating in electric mode have been found to be quieter than conventional cars. As a result, the auditory cues which pedestrians and cyclists use to assess the presence, proximity and location oncoming traffic may be reduced, posing a safety hazard. This laboratory study examined auditory localisation of conventional and electric cars including vehicle motion paths relevant for cycling activity. Participants (N = 65) in three age groups (16–18, 30–40 and 65–70 year old) indicated the location and movement direction (approaching versus receding) of cars driven at 15, 30 and 50 km/h in two ambient sound conditions (low and moderate). Results show that low speeds, higher ambient sound level and older age were associated with worse performance on the location and motion direction tasks. In addition, participants were less accurate at determining the location of electric and conventional car sounds emanating from directly behind the participant. Implications for cycling safety and proposals for adding extra artificial noise or warning sounds to quiet (electric) cars are discussed.     

Investigations into pedestrian crossing choices on Cape Town freeways

South Africa is regularly identified in international literature as one of the countries with the highest number of traffic deaths per capita. Of these, around one third are pedestrians. Freeways constitute one of the highest risk locations for pedestrians – in most developed countries pedestrians are not seen in such locations, but for many South African pedestrians freeways are a regular part of their commute. Walking alongside and crossing of freeways are extremely common – and deaths associated with such activity also tragically so. Over the past four years in the Cape Town area alone there have been 413 pedestrian crashes causing 139 pedestrian deaths on freeways, as well as an unrecorded number of serious injuries.While pedestrian crossing behaviour has been extensively researched in many parts of the world, almost none has so far been carried out in the context of freeways. Little is known about pedestrian crossing decisions in locations where the stakes are so high.Following a study using traffic cameras associated with the Freeway Management System to measure the frequency and location of pedestrians crossing freeways, this article reports on surveys into crossing decisions of pedestrians on Cape Town’s freeways. Two successive surveys were conducted with pedestrians on or alongside the freeway. These included pedestrians who crossed using footbridges, and pedestrians who crossed at grade.In the analysis it was clear that while some of the traditional factors such as time saving and convenience were considered, far more important to pedestrians were issues of safety. Safety from fast-moving vehicles was one factor, while safety from criminals was a second and often conflicting factor which affected crossing choices. Crossing at grade was partly described in terms of utility maximisation (time and distance saving) but it was also, for many, one way of avoiding becoming a victim of crime. In terms of their perceptions of being involved in crashes, at-grade crossers reflected an astute awareness of the risks that they face. Many pedestrians articulated the belief that their choice of crossing was constrained by lack of alternatives. Until public transport and safe crossing locations are provided for these pedestrians it is clear that many will continue to cross dangerous roads, in full awareness of the risks they face.     

A simulator study of factors influencing drivers’ behavior at traffic lights

Drivers’ reactions to changing traffic lights have an impact on safety at intersections. We examined the influence of transient factors – more specifically time pressure and social context, both conducive to traffic-light violation – on behavior behind the wheel when a traffic light changes. We carried out an experiment on a driving simulator. The participants were 94 car drivers (53 males) with a mean age of 21.7 years. They drove under time pressure vs. no time pressure. At several intersections the participants were alone (no other drivers present), whereas at several other intersections they were behind a line-up of vehicles, the last of which ran the yellow light (other drivers present). As expected, time pressure and social context (presence of other drivers) increased participants’ risky behaviors while approaching, and going through traffic lights, as well as undesirable rapid accelerations when the signal changes to green. The effect of time pressure on yellow-light running was not mediated by approach speed, which showed that participants in a hurry were likely to run lights intentionally. The results are interpreted in view of proposing effective measures for reducing yellow-light running and rapid accelerations at traffic lights.