Investigating the impact of a novel active gap metering signalization strategy on driver behavior at highway merging sections

A safe headway to the lead vehicle is important to reduce conflicts with merging vehicles from highway on-ramps. Previous research has outlined the advantage of gap metering strategies to yield sufficient space to merging vehicles and improve highway capacity during peak hours. However, prevailing gap metering systems fail to indicate the minimum required gap and leave it to the drivers’ judgment to adjust their headway. This paper proposes a new Active Gap Metering (AGM) signalization that helps outer lane drivers to adjust their headway to the lead vehicle when approaching highway ramps with incoming vehicles. This AGM signalization represents a combination of pavement markings and an innovative Variable Message Sign (VMS). The AGM system was tested alone and in combination with additional variable speed limits (VSL) in distinct environments of the Doha Expressway in the State of Qatar using a driving simulator. The driving behavior of 64 drivers was analyzed using repeated-measures ANOVA. The results showed that the AGM effectively influenced the drivers’ behavior on the right stream lane. Drivers did gradually increase the distance to the lead vehicle, which resulted in optimal headways to merging on-ramp vehicles. Most importantly, the minimum time-to-collision (TTC_min) to the merging vehicle was increased by an additional 1–1.5 s as compared to no treatment. The proposed AGM signalization can, therefore, be considered by policymakers to influence drivers’ headways at critical merging sections.     

Effects of forward collision warning technology in different pre-crash scenarios

The forward collision warning (FCW) system is expected to reduce rear-end crashes; however, its effects on driving behavior and safety have not been thoroughly investigated, specifically the effect variations between different pre-crash scenarios. To identify these variations, this study conducted a driving simulator experiment and compared the FCW’s effects between three pre-crash scenarios: the freeway scenario, the arterial scenario and the intersection dilemma zone scenario. Thirty-nine participants were involved in the experiment. The results showed that the adaptation of driver behavior in impending rear-end collision events resulted from both the FCW and the scenario. The intersection dilemma zone scenario has indications of slowing down, which encouraged drivers to take a more aggressive response strategy under the FCW; the arterial scenario might be regarded as an “easy-to-handle” situation in which a significant portion of drivers adopted moderate level of response strategy under the FCW; both the intersection dilemma zone scenario and freeway scenario have burdened driving tasks, and this might deteriorate a driver’s ability to adapt to the FCW. In addition, different types of drivers experienced varied benefits from the FCW in each scenario. The FCW would be particularly recommended for non-experienced drivers in the freeway scenario and for female drivers in the arterial scenario; moreover, in the scenario of the intersection dilemma zone, the FCW would be particularly recommended for drivers who have a crash/citation before. The results also support specific FCW designs which are able to highlight the collision risk. This study demonstrated that it would be better to indicate the effects of the FCW under the restriction of specific scenario features and develop the FCW based on that.     

Relationships between personality facets and accident involvement among truck drivers

Prior research on the personality characteristics of truck drivers and accident involvement has relied primarily on the Big Five personality factors (e.g., Extraversion), and has largely focused on self-reported number of accidents rather than more objective, independent records. We examined the association between personality characteristics and accidents among professional truck drivers at the facet level of personality using company records of accidents over time. Analyses suggested that more empathetic individuals had lower rates of accident involvement, whereas more anxious, guilt-prone, exhibitionistic, and risk-taking individuals had higher rates. We discuss implications for decreasing rates of accidents, the selection of drivers, and use in other industries where physical safety is a concern.     

Cognitive-behavioural interventions in a patient with an anxiety disorder related to diabetes

This study extends the data on the efficacy of cognitive interventions for patients with chronic medical problems and describes the case of a 37-year-old woman with an anxiety disorder related to diabetes. The effects on panic frequency, use of safety behaviour and related beliefs were investigated after the introduction of two main cognitive-behavioral interventions. The results are consistent with predictions from the cognitive model of panic. This case demonstrates the usefulness of directly challenging the 'meaning' of the feared situation in order to produce clinically significant improvements in the management of physical disease.     

Supervisory interpretation of safety climate versus employee safety climate perception: Association with safety behavior and outcomes for lone workers

Research has shown that safety climate predicts safety behavior and safety outcomes in a variety of settings. Prior studies have focused on traditional work environments in which employees and supervisors work in the same location and the mechanisms through which safety climate affects behavior are largely understood. However, the nascent research examining safety climate among lone workers suggests that safety climate may have some uniqueness in this context. Based on leadership theories and utilizing an exploratory approach, this study increases our understanding of the lone worker context by examining employee perception of safety climate and supervisory interpretation of safety climate; how similar or different they are, and how they are related to important safety outcomes. Surveys were administered to a matched sample of 1831 truck drivers and their 219 supervisors at four different trucking companies. Objective data on employee injuries were collected six months after survey administration. The results provided support for the measurement equivalence of the Trucking Safety Climate Scale at the organization level for both employee and supervisor respondents. For both organization- and group-level safety climate, employee perceptions of safety climate and supervisory interpretation of safety climate were significantly different, such that supervisors provided higher ratings for both safety climate sub-scales. Further, only employee safety climate perceptions significantly predicted self-reported safety behavior (directly) and objective injury outcomes (indirectly). This suggests that when trying to gauge and improve upon a trucking company’s safety climate, we should rely on employee perspectives, rather than supervisory interpretation, of safety climate.     

Physiological markers of traffic-related stress during active travel

Understanding perceptions of safety and comfort (PSC) while walking or cycling is essential to accommodating and encouraging active travel, but current measures of PSC, primarily surveys, suffer from validity and reliability issues. Physiological markers of stress like electrodermal activity and heart rate variability have been proposed as alternative, objective measures of PSC. This paper presents a literature summary and conceptual framework examining the use of physiological stress markers during walking and cycling. The existing studies of active traveller stress markers report inconsistent findings and account for limited controls. We propose a comprehensive conceptual framework to describe the array of dynamic stimuli experienced during active travel, with complex appraisals and multidimensional stress responses that feedback to travel behaviour and stimuli exposure, and culminate in a set of physiological outcomes triggered by activation of the autonomic nervous system – all moderated by numerous personal and trip-related factors. The key challenge of inferring traffic-related fear or discomfort from physiological markers measured on-road is potential confounding effects of: (1) non-traffic factors that induce or modify stress responses, (2) traffic factors that induce stress responses not associated with safety or comfort, and (3) personal and environmental factors that directly influence physiological measurements outside of a stress response. No physiological stress marker has yet been shown to be reliable for on-road active travellers, particularly not for inter-subject comparisons. Physiological markers have the potential to provide high-resolution, objective information about pedestrian and cyclist PSC, but further research, particularly controlled experiments, and more precise study framing are needed to ensure validity and address moderating and confounding factors.     

Factors associated with cyclists’ self-reported choice of lane position

Riders cycling on roads without bicycle lanes are generally advised to ride in the centre of their lane (primary position), and to move toward the left of the lane (in left-hand traffic; secondary position) only to let faster traffic pass and when it is safe. The present research investigated which situational and personal characteristics were associated with choice of lane position, and whether choice of lane position is associated with on-road crash involvement. A large cohort of bicycle riders from New South Wales Australia reported on their cycling patterns and crashes in 6 reporting weeks over a 1-year period using on-line surveys. During one reporting week 1525 participants identified their preferred choice of lane position in each of 6 visually-depicted scenarios that were designed to investigate the influence of number of lanes (in the cyclists’ direction of travel), parked cars, and bus lanes. A majority of respondents preferred the secondary position in scenarios with a clear kerbside lane. Respondents were significantly more likely to choose the primary position in multiple-lane situations compared to single-lane situations, if there were parked cars in the kerbside lane, and if they were female, younger, experienced riders, transport riders, or high intensity riders. Controlling for personal characteristics, choosing the primary position in a single clear traffic lane scenario was associated with a higher on-road crash rate, while choosing the primary position in a traffic lane with parked cars scenario was associated with a lower on-road crash rate. Results suggested that when riding on-road the bicycle riders in this Australian cohort prefer to keep their distance from motorised traffic, allowing traffic to pass safely when space allows. Nonetheless, results suggested that choice of lane position is highly dependent on the local road and traffic environment. Further research is needed to support advice to cyclists.     

Evaluation of user behavior and acceptance of an on-bike system

In this study, users’ acceptance of an on-bike system that warns about potential collisions with motorized vehicles as well as its influence on cyclists’ behavior was evaluated. Twenty-five participants took part in a field study that consisted of three different experimental tasks. All participants also completed a follow-up questionnaire at the completion of the three-task series to elicit information about the acceptance of the on-bike system. In the experiment phase, participants were asked to ride the bicycle throughout a circuit and to interact with a car at an intersection. Participants completed three laps of the circuit. The first lap involved no interaction with the car and served the purpose of habituation. In the second and third laps participants experienced a conflict with an incoming car at an intersection. In the second lap, the on-bike device was not activated, while in the third lap, participants received a warning message signaling the imminent conflict with the car. We compared the difference in user’s behavior between the second lap (conflict with a car without the warning of the on-bike system) and the third lap (conflict with a car with the warning of the on-bike system). Results showed that, when entering the crossroad, participants were more likely to decrease their speed in case of warning of the on-bike system. Further, the on-bike system was relatively well accepted by the participants. In particular, participants did not report negative emotions when using the system, while they trusted it and believed that using such technology would be free from effort. Participants were willing to spend on average 57.83 € for the system. This study highlights the potential of the on-bike system for promoting bicycle safety.     

伦理型领导如何影响员工创造力:心理安全感与关系的作用

基于认知评价理论,以配对的328组员工为样本,探讨了伦理型领导与员工创造力的关系,及心理安全感、上下级关系在这一关系中的作用。结论:伦理型领导与员工心理安全感正相关;上下级关系与伦理型领导的交互作用强化了员工的心理安全感;心理安全感中介了伦理型领导对员工创造力的影响;上下级关系调节了心理安全感对伦理型领导与创造力关系间的中介作用。     

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.