This study develops and validates a smartphone-based framework for automatically detecting emergency maneuvers, strong jolts, and crashes involving electric scooters and electric bicycles. Detection criteria were established through controlled track experiments and subsequently evaluated using data collected during a naturalistic riding study involving 119 participants and more than 26,000 km and 1,600 h of riding, combining accelerometer, gyroscope, GPS, and video recordings. Threshold-based detection criteria were defined using variables selected for their physical relevance and ability to discriminate between target and non-target situations. Hard braking, sharp turns, strong jolts, and crash-related events were identified using combinations of acceleration, jerk, rotational dynamics, and post-event vehicle motion. Video review showed that 74% of hard-braking detections corresponded to harsh-braking maneuvers, 64% of sharp-turn detections reflected genuine avoidance maneuvers, and 91% of strong-jolt detections were associated with infrastructure features. Video verification of collision candidates confirmed several reported and previously unreported impacts, including collisions with other road users and single-vehicle falls. Application of the framework to the naturalistic dataset revealed marked differences between vehicle types. E-scooter users experienced higher rates of hard braking and strong jolts than e-bicycle users, reflecting behavioral differences and vehicle characteristics. Illustrative mapping examples showed that detected events and rider-reported hazardous situations could occur in close proximity, suggesting opportunities for future spatial analyses of micromobility safety. Although additional validation on larger crash datasets is required, the results demonstrate that threshold-based approaches can provide meaningful indicators of rider safety, support large-scale monitoring of micromobility risks, and contribute to infrastructure and transport-safety assessment.

OBJECTIVE:Powered 2-wheeler (PTW) safety remains a critical concern, prompting the investigation into the efficacy of advanced rider assistance systems (ARAS) in reducing crash rates. The objective of this study is to provide a comprehensive quantification of the effects of 2 such systems, Adaptive Cruise Control (ACC) and Autonomous Emergency Braking (AEB), on the avoidance or mitigation of motorcycle crashes. METHODS:Using real-world motorcycle crash data, this research employed kinematic reconstruction techniques and numerical simulations to evaluate the impact of ACC and AEB on crash reduction. A parametric study was conducted, exploring various parameters including trigger distances, deceleration rates, and field of view, to assess their influence on the effectiveness of this systems in crashes involving PTWs. RESULTS:The analysis revealed significant findings regarding the effectiveness of ACC and AEB in reducing crash rates involving motorcycles. Notably, ACC, especially in dynamic mode with a trigger distance of 40 m, demonstrated the ability to prevent 53% of crashes, resulting in impact speed reductions ranging from 4 to 25 km/h. Similarly, AEB exhibited remarkable effectiveness, reducing impact speeds by 2.5 to 38.9 km/h, with avoidance rates ranging from 7% to 63%. CONCLUSIONS:Optimization of key parameters such as triggering strategy, deceleration, sensor range, and field of view is crucial for maximizing the effectiveness of ARAS in motorcycle safety applications. These findings provide valuable insights for manufacturers and policymakers, highlighting the need for tailored approaches to system design and implementation. By refining these systems based on empirical data and analysis, significant improvements can be made in motorcycle safety, ultimately saving lives and reducing the severity of crashes on roadways.

The increasing popularity of Electrically Assisted Personal Mobility Vehicles (e-PMVs) represents a significant shift in urban transportation, offering flexibility and environmental benefits, yet raising safety concerns, particularly regarding accidents involving vulnerable road users. Research on the dynamic performance of these vehicles is essential to address such concerns and ensure safer interaction with other vehicles and ease their integration into urban traffic. This study explores the longitudinal (braking and acceleration) and lateral (avoidance and slalom) performances of e-PMVs through 127 controlled track tests conducted by three e-scooter riders, two e-bicycle riders, and one e-monowheel rider using one of the most common models of these vehicles. Specific performance indicators were defined for each maneuver to evaluate and compare dynamic capabilities. Results show that e-bicycles exhibits the most effective braking performance, achieving decelerations close to 6 m/s², while e-scooters and e-monowheels demonstrate lower deceleration rates around 3.7 m/s² and 2.8 m/s², respectively. Acceleration is quite similar across vehicles, ranging from 0.7 to 0.9 m/s² in sport/turbo mode. Performance differences during evasive maneuvers are minimal, with maximum roll rate ranging between 70 and 110°/s and maximum roll angle between 15° and 22° In slalom, the e-monowheel shows the highest roll rate at 102°/s, followed by the e-bicycle at 87°/s and the e-scooter at 69°/s. The study highlights that e-PMVs, particularly e-scooters and e-monowheels, have substantially lower braking and acceleration capabilities than conventional motor vehicles, which likely increases the risk of traffic conflicts escalating into accidents. By filling a gap in the experimental knowledge base, especially concerning monowheels, these findings underscore the need for further research aimed at improving the design and safety features of e-PMVs, prioritizing improvements in braking efficiency and maneuverability to mitigate potential risks and offer users a safer mode of transportation.

The growing popularity of electric personal vehicles has led to new challenges and an increase in accidents. This study aims to analyze risky situations among e-scooter and e-monowheel users by examining perceived, observed and measured data to gain a comprehensive understanding of safety issues. Over two months in the South region of France, the daily trips of 25 e-scooter and 5 emonowheel drivers were recorded using smartphones, including vehicle dynamics data and video footage. The participants could report critical events in real-time. The experiment recorded 1559 trips and 115 critical events. Most interactions occurred on the road, involving motorists and pedestrians, often at intersections and during daylight. Drivers attributed responsibility as follows: 20% to themselves, 65% to others, and 15% shared, with 9% of traffic offenses reported. Causes primarily revolved around non-compliance with traffic regulations, failure to signal driving intentions, and right-of-way violations. Video and measured data accurately captured 80% of events, with 77% of them matching the declared emergency maneuvers, typically hard braking and/or avoidance. 10% of the critical events were classified as very serious and 21% as serious. Some differences emerged between e-scooter and e-monowheel users' critical events. Similar naturalistic driving studies in Lyon and Paris will provide valuable additional data.

OBJECTIVE:In Europe, Powered Two-Wheelers (PTW) riders are involved in 15% of all traffic fatalities and the most serious injuries are sustained on the trunk and the head. The aim of this work is to study motorcyclist impact conditions through the reconstruction of 8 real accidents leading to AIS3+ trunk injuries. METHODS:Based on multi-body simulations, key parameters such as impact speed, body impact angles and impacted obstacles are deeply analyzed to determine their influence on injury severity. RESULTS:Oblique and lateral impacts tend to increase the risk of rib fractures. Trunk impacts against vehicles show predominant normal speed components (25-40 km/h), while impacts with the ground have higher tangential speeds (40-50 km/h). Two main impact configurations for the trunk are proposed to reproduce impact conditions during PTW accidents causing AIS3+ trunk injuries. CONCLUSION:This study allows a better understanding of trunk injury mechanisms in PTW accidents and can be used to improve protective device design.

Advanced Rider Assistance Systems (ARAS) are solutions developed to reduce the crashes rate of Powered Two Wheelers (PTWs). They assist riders in their driving task by transmitting information on their environment or by automatically controlling the dynamics of their vehicle. This study describes a methodology for evaluating the impact of 14 ARAS on PTWs crashes. This methodology consists first of establishing links between ARAS functionalities and riders' failures in crashes situations. Then, an analysis of real crashes cases was conducted using two reals crashes databases: the “In-depth crashes investigation at the Laboratory of Accident Mechanisms Analysis (LMA)” in Salon-de-Provence, France, and the “Initiative for the Global harmonization of Accidents Data”. A total of 390 crashes were analyzed. The results showed that ARAS had an influence on 61.5% of the crashes studied. ARAS benefits at the French national level were also assessed, with a weighting of the results obtained. In the French national data, the Anti-lock Braking System had the highest overall impact among the ARASs, estimated to have influenced 39.1% of crashes. Next, emergency braking systems influenced 30.1% of crashes, and an anti-collision warning system had an impact on 29.8% of crashes. This work provided an initial assessment of the most promising technologies for PTWs road safety. It could be used to guide industry and road safety policy towards the development of the most beneficial systems, and the introduction of standards or regulations.

BackgroundHelicopter evacuation is crucial for providing medical care to casualties. Previous civilian studies have demonstrated that air transport can enhance survival rates compared with ground transport. However, there has been limited research on specific accelerations during helicopter flights, particularly in military flights. This study aims to analyse and compare the accelerations endured during civilian and military helicopter evacuations.MethodsAccelerations were recorded during evacuation flights from the site of injury to the first medical responders in civilian helicopter EC135 T1, and military Puma SA.330 and Caiman NH90 TTH helicopters. The research investigated global acceleration and compared acceleration distributions along the vertical, lateral and longitudinal axes. A specific comparative study of the take-off phases was also performed.ResultsThe analysis showed that vertical loads caused the most extreme accelerations for all types of helicopter but these extreme accelerations were rare and lasted for less than 1 s. Military flights show similar acceleration intensities to civilian flights, but accelerations are higher during short periods of the take-off phase.ConclusionsThe findings suggest that helicopter evacuations during military operations are as safe as civilian evacuations and highlight the importance of patient positioning in the aircraft. However, further research should investigate the haemodynamic response to accelerations experienced during actual evacuation flights.

Non-inflatable chest protector is a passive safety device to protect powered two-wheeler (PTW) riders from thorax injuries. Before being put on the market, the protectors should be qualified for the European standard tests EN1621-3:2018 which remains uncertain regarding the impact energy level, force evaluation thresholds, and impact configurations. This study aims to ascertain whether the standard EN1621-3:2018 ensures adequate chest protection for PTW riders. Thus, three generic protectors were created to qualify for standard tests and then evaluated against rider chest impact scenarios by finite element modelling. Bar-to-rider and rider-to-bar virtual impacts were simulated with a range of impact energy 50 similar to 1563 J. In virtual standard tests, protector 1 had the lowest impact force, followed by protectors 2 and 3. In chest impact analysis, the rider with or without protector was rarely found injured under the testing standard energy level (50 J). The chest impact force was below the standard force threshold of 24 kN under all impact energy levels. Protector 3 had a generally better protection performance in terms of chest deflection than protectors 1 and 2, which were not consistent with the standard testing results. The rider chest responses in bar-to-rider impacts differed significantly from the responses in bar-to-rider impacts. Therefore, future testing standard might introduce more appropriate impact energy, force thresholds and accident-relevant impact configurations to ensure the device's effectiveness in providing protection during PTW crashes. This study furnishes valuable insights into enhancing the design and evaluation methodologies of protective gear, thus directly contributing to the advancement of PTW rider safety.

The risk of serious crashes is much higher for motorcyclists than for motorists, yet there is a lack of knowledge about their behavior and performance on the road. This paper aims to compare the actual use of PTWs' dynamic capacities to that of passenger cars, based on objective data collected during three naturalistic driving/riding studies conducted in France between 2012 and 2018. Motorcyclists accelerate and brake more often and with greater intensity. PTWs endure medium to high yaw rates slightly more often than cars, and sometimes reached very high levels never endured by cars. The comparison of speeds is more contrasted and does not confirm the common belief that motorcyclists often ride faster than motorists drive.

Investigating psychological characteristics and dynamic behaviors can provide insight in the behavior of at-risk drivers. Achievement goals in driving have recently been studied to assess driver motivation. The four achievement goals in driving are mastery-approach, performance-approach, mastery-avoidance, and performance-avoidance. Three dynamic criteria have been developed to objectively characterize driver behavior: time spent above acceleration thresholds; driving incidents; the extent of dynamic loading. The aim of this study was to examine the predictive role of achievement goals on objective driving behaviors. During 8 months, 4,626,379 km of 299 drivers was recorded, and simultaneously, the Achievement Goals in Driving Questionnaire was completed. Mastery- approach goals seem to be the most protective goals in driving, as opposed to performance-approach goals.

Implicit theories focus on how ability may be perceived by individuals. There are two main beliefs: entity beliefs (i.e., driving ability is a gift) and incremental beliefs (i.e., driving ability is improvable through effort). Implicit theories have been studied in various domains (e.g., education, sport), but never in driving, even though they could improve the knowledge of drivers' psychological characteristics. The first objective of the present study was to develop and validate a questionnaire measuring implicit theories in driving. The second objective was to assess the predictive role of implicit theories on violations and driving self-efficacy, and the moderating role of gender. In study 1, confirmatory factor analysis, analyses of gender invariance, and concurrent validity were assessed to validate the questionnaire named Implicit Theories in Driving Questionnaire (ITDQ). In study 2, the predictive role of implicit theories on violations and driving self-efficacy was evaluated using multiple regression analyses. Moderation analyses evaluated the moderating role of gender on the relationships between implicit theories and violations, along with driving self-efficacy. The ITDQ showed acceptable psychometric properties. The results highlighted that entity beliefs positively predicted aggressive violations and negatively predicted driving self-efficacy. Conversely, incremental beliefs negatively predicted ordinary violations and positively predicted driving self-efficacy. The ITDQ is a valid scale now available for assessing implicit theories in driving, that have been shown to influence self-reported driving behavior. Future research on implicit theories in driving may help to better understand the psychological characteristics of at-risk drivers and improve driver's training, to reduce the number of road accidents.

Investigating psychological characteristics through self-reported measures (e.g., anger, sensation seeking) and dynamic behaviors through objective measures (e.g., speed, 2D acceleration, GPS position etc.) may allow us to better understand the behavior of at-risk drivers. To assess drivers’ motivation, the theoretical framework of achievement goals has been studied recently. These achievement goals can influence the decision-making and behaviors of individuals engaged in driving. The four achievement goals in driving are: seeking to improve or to drive as well as possible (mastery-approach), to outperform other drivers (performance-approach), to avoid driving badly (mastery-avoidance), and to avoid being the worst driver (performance-avoidance). Naturalistic Driving Studies (NDS) provide access to the objective measurements of data not accessible through self-reported measurements (i.e., speed, accelerations, GPS position). Three dynamic criteria have been developed to characterize the behavior of motorists objectively: driving events, time spent above acceleration thresholds (longitudinal and transversal), and the extent of dynamic demands. All these criteria have been measured in different road contexts (e.g., plain). The aim of this study was to examine the predictive role of the four achievement goals on these objective driving behaviors. 266 drivers (96 women, 117 men) took part in the study, and 4 242 482 km was recorded during 8 months. Simultaneously, they completed the Achievement Goals in Driving Questionnaire. The main results highlighted that mastery-approach goals negatively predicted hard braking and the extent of dynamic demands on plain and hilly roads. Mastery-approach goals seem to be the most protective goals in driving. Future research on the promotion of mastery-approach goals in driving may be able to modify the behavior of at-risk drivers.

In the event of a road accident, a quick intervention is crucial. The mobile emergency services take care of patients whose condition requires an emergency repatriation to a hospital, by land in an ambulance or by air in a helicopter. The main criteria for choosing the means of transport are the time required for repatriation and the patient’s more or less critical state of health. Do the vehicle dynamic effects endured by the transported patient have an influence on their health condition? Vehicle dynamics data were recorded with a road data recorder for a period of 3 months, under real conditions of patient repatriation to a hospital; 39 trips were recorded by ambulance and 29 trips by helicopter. Significant differences in speed (average 42 versus 202 km/h) and distance travelled (average 23 versus 85 km) were observed. The sustained effects are similar in helicopters and ambulances. The ambulance causes more abrupt variations in longitudinal and transversal directions, whereas the helicopter has more variations in vertical direction. The vibration level in helicopters is higher than in ambulances. These results can be considered as a first reference baseline for establishing a characterization of transported patients’ exposure to vehicle dynamics.