The safety performance of connected vehicles on slippery horizontal curves through enhancing truck drivers’ situational awareness: A driving simulator experiment

Although drivers can adequately adjust their operating speed according to the road curvature, they show a lack of recognition regarding the pavement friction conditions. In this regard, inappropriate speed selection on Horizontal Curves (HCs) with reduced surface friction can lead to a remarkable rate of run-off-road, sideswipe, head-on, and rollover crashes, especially on rural highways. Aligned with the Connected Vehicle (CV) Pilot Program on Interstate-80 in Wyoming, this study scrutinizes how CV advisory/warning messages can enhance traffic safety on slippery HCs. To this aim, a roadway consists of two HCs with regular and slippery pavement conditions was designed in a high-fidelity driving simulator experiment. A total of 24 professional truck drivers were recruited to drive the simulated roadway under CV and non-CV environments. In the CV scenario, drivers were informed about the pavement conditions and the advisory speeds before entering HCs. In contrast, no messages were given to non-CV drivers. Truck drivers' behaviors in both scenarios were quantified using four Kinematic-based Surrogate Measures of Safety (K-SMoS), including deviation from the pathway, instantaneous acceleration, lateral speed, and steering angle. CVs’ trajectories were statistically compared to non-CVs in terms of the central tendency and dispersion using the Wilcoxon Signed-Rank Test (WSRT) and Median Absolute Deviation (MAD), respectively. The results of WSRT depicted, under the effect of CV advisory/warning messages and throughout the slippery HC, the central tendency of four K-SMoS could be shifted toward zero by 23% up to 99%. This shifting is associated with a significant safety enhancement that potentially can reduce the likelihood of curve-related crashes on slippery HCs. It was revealed that the variation in drivers’ behavior on the slippery HC could be minimized in the CV environment, where 54% up to 95% reduction in the dispersions of four K-SMoS were observed, leading to more certainty in drivers’ behavior.     

The influences of listening and speaking on pedestrians' assessments of approaching vehicles

Research suggests a relationship between auditory distraction (such as environmental noises or a vocal cell phone conversation) and a decreased ability to detect and localize approaching vehicles. What is unclear is whether auditory vehicle perception is impacted more by distractions reliant on listening or distractions reliant on speaking (analogous to the two components of a vocal cell phone conversation). In two experiments, adult participants listened for approaching vehicle noises and while performing listening- and speaking-based secondary tasks. Participants were tasked with identifying when they first detect an approaching vehicle and when they no longer felt safe to cross in front of the approaching vehicle. For both experiments, the speaking task resulted in significantly later detection of approaching vehicles and riskier crossing thresholds than in the no-distraction and listening conditions. The listening secondary task significantly differed from the control condition in experiment 1, but not experiment 2. Overall, our results suggest auditory distractions, particularly those reliant on speaking, negatively impact pedestrian safety in situations where visual information is minimal. Results may provide guidance for future research and policy about the safety impacts of secondary tasks.     

Effects of a driver assistance system with foresighted deceleration control on the driving performance of elderly and younger drivers

It is imperative to enhance the safety of elderly individuals on the roads to ensure the quality of their daily life. Near-miss incidents or accidents at blind intersections often result from a conflict between the behaviors of the driver and of other road users (pedestrians and cyclists). The failure to search for potential conflict in the context of blind intersections is a concern pertaining to road safety. The proposed assistance system performs a proactive braking intervention to achieve a referenced velocity in uncertain situations, such as one in which an unobserved pedestrian might initiate a road crossing. The proactive braking intervention attempts to manage the potential risk of crashing with respect to covert hazards. Because an automated system may impair a human’s ability to perceive and respond to hazardous situations while driving, this study was designed to examine the effects of proactive braking intervention and visual support cues on elderly and younger drivers’ ability to respond to information about potentially hazardous situations. We conducted a public-road driving experiment involving 108 elderly and younger drivers from two non-overlapping age groups. It was observed that the vehicle slowdown realized through the proactive braking intervention enabled the drivers to perform safety confirmation near blind spots and caused them to be more sensitive to and wary of potential hazards. This approach could be effective not only for elderly drivers, but also for young or inexperienced ones.     

Hazard-based duration approach for understanding pedestrian crossing risk exposure at signalised intersection crosswalks – A case study of Kolkata,India

Pedestrian signal violation is a significant concern among policymakers and traffic engineers as this leads to a pedestrian-vehicle crash. The waiting time for a pedestrian at intersections is crucial in street-crossing decision-making. Once pedestrians terminate their waiting behaviour during the red-light period, they would cross in the red light and put themselves in danger. A total of 2089 red-light arriving pedestrian observations were made at eight intersection crosswalks across Kolkata city (India). With the help of hazard-based duration models, the waiting duration till signal violation has been analysed. Kaplan–Meier curve has been plotted to understand the survival probabilities. A semi-parametric Cox Proportional Hazard model was used to understand the different factors influencing signal violation behaviour. However, the proportional hazard assumption was not satisfied. Therefore, a parametric Accelerated Failure Time (AFT) model was used to understand the various covariates that affect the waiting duration. The results highlighted that 49.5% of pedestrians crossed immediately after arriving at the intersection in the red-light phase. A pedestrian’s probability of crossing the road when it is unsafe, i.e., motor vehicles still have green or yellow, varies with the waiting time. As waiting time increases, pedestrians get impatient and violate the traffic signal. This violation places them at an increased risk of being struck by a motor vehicle. The covariate analysis using the AFT model showed that pedestrian glance/looking behaviour, different types of distractions, signal cycle length, carrying luggage, and traffic plying on the road impacted signal violation behaviour. Signal modifications by reducing red-light phase length for pedestrians might be the most efficient means of reducing the likelihood of signal violation and being hit by a motor vehicle.     

Investigating relationships among perceptions of yielding,safety, and comfort for pedestrians in unsignalized crosswalks

Interactions with other road users influence the perceived safety and comfort of pedestrians. Yet the relationships among perceptions of yielding, safety, and comfort are poorly understood. To enhance understanding of these key concepts, the objectives of this study are to determine how perception of pedestrian safety at unsignalized crosswalks differs from perception of comfort, and the relationship of each with perception of yielding. A generalized structural equations model is developed using data from an online survey in which 366 participants (i.e., “perceivers”) rated yielding, safety, and comfort for sample videos of pedestrian interactions with motor vehicles and bicycles. Results show that an individual’s perception of yielding plays a crucial role in mediating the effects of interaction attributes (e.g., vehicle speed, proximity) and perceiver attributes (e.g., travel habits) on their perceptions of pedestrian safety and comfort. For example, people who bicycle more frequently perceive pedestrians as more comfortable than people who walk more frequently, rooted in misalignment on what constitutes adequate yielding. Strategies to address pedestrian comfort can focus on a set of key yielding behaviors by drivers and cyclists – particularly allowing the pedestrian to cross first. Motor vehicle drivers must exhibit stronger yielding behavior (e.g., allow a larger time gap) than bicycles to achieve the same level of perceived pedestrian safety and comfort. Although perceptions of safety and comfort are strongly related and similarly impacted by yielding, researchers should be cautious about using the concepts interchangeably because they are differently impacted by attributes of the interaction and perceiver.     

Mastering balance: The use of balance bicycles promotes the development of independent cycling

Children who learn to cycle at a young age do this by using training bicycles that simplify control requirements compared with regular bicycles, such as bicycles with training wheels or balance bikes without pedals. The primary purpose of the current study was to investigate whether the two types of training bicycles result in a different age of onset of independent cycling on a regular bicycle. We asked parents of 4- to 6-year-old children (n = 173) to complete a questionnaire regarding their child's bicycling history. The results showed that children who had practised with a balance bicycle started practising at a younger age, had shorter practice duration, and were able to cycle independently at a younger age in comparison to children who had practised with a bicycle with training wheels (or with both training bicycles). We argue that the observed advantage of balance bicycle is associated with the balance bicycle actively challenging postural control. Further research is needed to uncover the impact of training bicycles on the further development of the foundational skill of cycling.     

A systematic review of observational studies investigating the influence of mobile phone distraction on road crossing behaviour of pedestrians

The growing prevalence of technological distractions amongst pedestrians makes it an important road safety concern. Observational studies are considered a reliable method to investigate the influence of mobile phone distraction on pedestrian road crossing behaviour and crash risks. The present study conducts a systematic review of international literature on pedestrian distraction observations by following the Preferred Reporting Items for Systematic Reviews and meta-Analyses (PRISMA) guidelines. A total of 792 studies were identified from the literature search on six research databases: Scopus, Google Scholar, Web of Science, PubMed, Cochrane library, and Transportation Research International Documentation (TRID). Finally, 39 research articles were assessed using the systematic classification scheme based on the following five research aspects: prevalence of mobile phone distraction, study locations, performance measures, analysis techniques, and additional factors associated with mobile phone use among pedestrians. Over 35% of the studies were conducted in the United States of America (USA) and 69% of the investigations were done in the last five years. Overall, the findings across the studies indicate that mobile phone distraction plays a major role in pedestrian risky road crossing behaviour and violation tendencies. Visual distractions (such as texting) exhibited higher behavioural impairment compared to cognitive distractions (e.g., listening to music, and conversations). Pedestrian characteristics such as gender and age were the key factors examined in 77% and 67% of the observational studies. Finally, important directions for future research are illustrated to aid the researchers working in the area of pedestrian safety.     

Illusion of safety? Safety-related perceptions of pedestrians and car drivers around 3D crosswalks

Facilitating safe pedestrian road crossings is a major prerequisite for safe urban environments. In multiple cities around the world, 3D crosswalks have been painted, which provoke an optical illusion, of e.g., a crosswalk floating above the road, in car drivers who approach the crosswalk. However, to date, no detailed study of road users’ safety related perceptions on 3D crosswalks has been conducted. Hence, we investigated car drivers’ and pedestrians’ perceptions of a 3D crosswalk, and how they rate its safety in comparison to traditional (non-3D illusion) crosswalks. In an on-site questionnaire survey, we interviewed 201 pedestrians and 102 car drivers in the direct vicinity of a newly painted 3D crosswalk located in Yangon, Myanmar. Our results show that only 53.9 % of the car drivers report to have consciously perceived the 3D effect of the crosswalk. Nonetheless, both, pedestrians and car drivers rate the 3D crosswalk as safer for road crossing than a traditional crosswalk. A high share of pedestrians (43.3 %) report taking a detour to use the 3D crosswalk for road crossing. Approximately one third (31.3 %) of pedestrians and 48.0 % of car drivers interviewed have talked to their friends about the 3D crosswalk, indicating a high potential for using 3D crosswalks as a marketing tool for road safety actors to generate attention for pedestrian safety. Unrelated to our main research question, we found that pedestrians prefer to cross in groups, as it increases the perceived likelihood of cars yielding to them. Overall, the data points to significant increases in the perceived safety of drivers as well pedestrians around the 3D crosswalk. Future studies need to investigate how these perceptions translate to actual safety related behavior.     

Selective effects of excessive engagement in health-related behaviours on disgust propensity

The present study examined the extent to which engagement in health-related behaviours modulate disgust propensity, a purportedly stable personality trait. Participants were randomised into a health behaviour (n = 30) or control condition (n = 30). After a baseline period, participants in the health behaviour condition spent one week actively engaging in a clinically representative array of health-related behaviours on a daily basis, followed by a second week-long baseline period. Participants in the control condition monitored their normal use of health behaviours. Compared to control participants, those in the health behaviour condition reported significantly greater increases in disgust propensity after the health behaviour manipulation. This effect was most robust for contamination disgust propensity and remained significant when controlling for changes in health anxiety and disease fear. In contrast, self-disgust and anxiety sensitivity did not significantly differ between the two groups as a function of the health behaviour manipulation. Mediational analyses were consistent with the hypothesis that changes in the frequency of health-related behaviours, but not changes in health anxiety and disease fear, mediated the effects of the experimental manipulation on changes in contamination disgust propensity. These findings suggest that the purportedly stable personality trait of disgust propensity can be modulated by excessive engagement in health-related behaviours.     

Un point sur la responsabilité civile du fait des prothèses

The evolutions of the medical liability depend on the walking (step) of the jurisprudence, and on that of the European law. Crossings renewed the reflection on the consequences of the protheses failures, and make paradoxically return to the contractual obligation.