Investigation of accidents involving powered two wheelers and bicycles - A European in-depth study

Developing improved crash prevention approaches through in-depth investigation of motorcycle crash causation patterns

Despite advancements in road safety, Powered Two-Wheelers (PTWs) remain a vulnerable group with disproportionately high crash rates. This paper presents an in-depth analysis of PTW crashes in six European countries, with a case study of Loss of Control in Curves (LoCC), to address the gap between crash causation and prevention. By examining crash causation factors and their linkage to prevention strategies, the study illustrates various approaches for connecting causes and countermeasures. These approaches, which are applicable to different crash scenarios, include looking forward in the crash causation chains, looking backward, looking at only the last cause (critical events), or the first cause, or following a systemic approach. The research introduces a set of guidelines following the safe system approach, aiming to enhance the understanding of crash prevention among policymakers. The systemic approach to countermeasures, bridges the shortcomings of traditional crash causation studies that may exhibit bias or a narrow focus on "root causes". The proposed approach emphasizes the need for a comprehensive view of crash scenarios (i.e., considering the entire crash causation chain or multiple causation chains) and ensuring that preventive measures address the full spectrum of the system. It also takes in to account external factors such as cost, benefits, and politics, leading to improved road safety outcomes. The study findings are significant for researchers, since it is a step forward in in-depth crash causation studies, as well as road practitioners and policymakers, in providing a strategic framework for more effective and efficient road safety interventions.

Crash causation, countermeasures, and policy - Editorial

This editorial is both an introduction to the papers that make up this special issue (on the Relationship between Crash Causation, Countermeasures, and Policy) and an attempt at drawing conclusions. To assist the reader, we begin with a brief description of the subject matter of each paper. As expected, the authors tackle different aspects of this general topic and often differ in their conclusions. We follow up by asking: Are in-depth crash causation studies helpful? Can the need for understanding causation be defended? Does the Swiss Cheese Metaphor require revision? What are the building blocks on which the crash injury prevention programs rest? Can one really avoid comparing costs and benefits? These are some of the issues we raise and discuss. We end by offering for consideration a realistic model to link causes, countermeasures, policy, and responsibility for public safety.

Investigating and modeling motorcycle crash rates at urban unsignalized intersections in India

OBJECTIVE

The present study focuses on understanding the behavior of motorized 2-wheeler (MTW) riders at urban unsignalized intersections in India. In the Indian context, over 60% of road crash fatalities are attributed to vulnerable road users, with MTWs serving as the predominant contributors, accounting for 44% of total fatalities. Notably, unsignalized intersections have emerged as critical sites for accidents involving vulnerable road users.

METHODS

Postencroachment time is used to assess traffic conflicts of MTW users. Furthermore, the study employs the exceedance property of extreme value theory to calculate crash probabilities. Tobit and grouped random parameters Tobit regression models are developed to model crash probabilities, incorporating variables such as traffic volume, traffic composition, gap acceptance time, intersection characteristics, and intersection conflict area at 4 urban unsignalized intersections in Surat, India.

RESULTS

MTW riders have the lowest gap acceptance time among vehicles in the traffic stream. Cars and other heavy vehicles readily accept gaps when MTWs are in the conflicting stream at unsignalized intersections, which increases traffic conflicts. MTWs have the highest crash rates in the traffic stream. Among the developed models, the grouped random parameters Tobit regression captures the spatial unobserved heterogeneity of the study sites and outperforms the simple Tobit regression model. The results also indicate that MTW riders are exposed to a higher risk of crashes while turning at unsignalized intersections. The presence of a central traffic island has varied implications; it raises crash rates at 3-legged intersections but lowers them at 4-legged intersections for 2-wheelers.

CONCLUSION

The study concludes that MTW crash rates are influenced by traffic and intersectional factors. Increased gap acceptance time correlates with lower crash rates. Countermeasure selections require detailed investigations, because it was observed that the presence of central traffic islands has varied effects on crash rates at 3-legged and 4-legged unsignalized intersections.

Overview of road traffic injuries among migrant workers in Guangzhou, China, from 2017 to 2021

INTRODUCTION

There are many migrant workers in China's first-tier cities, but little is known about road safety. This paper systematically analysed road traffic injuries and risk factors among migrant workers in Guangzhou, China.

METHODS

Road traffic crash data from 2017 to 2021 were obtained from the Guangzhou Public Security Traffic Management Integrated System. We plotted the crash network of road users in road traffic crashes and used logistic regression to analyse the risk factors for migrant workers of motorcycle and four-wheeled vehicle crashes. Moreover, the roles of migrant workers and control individuals as perpetrators in road traffic crashes were also analysed.

RESULTS

Between 2017 and 2021, 76% of road traffic injuries were migrant workers in Guangzhou. Migrant workers who were motorcyclist drivers most commonly experienced road traffic injuries. Crashes between motorcyclists and car occupants were the most common. The illegal behaviours of migrant worker motorcyclists were closely related to casualties, with driving without a licence only and driving without a licence and drunk driving accounting for the greatest number. Migrant workers were responsible for many injuries of other road users. Motorcycle drivers have a higher proportion of drunk driving.

DISCUSSION

Migrant workers play an important role in road traffic safety. They were both the leading source of road traffic injuries and the main perpetrators of road traffic crashes. Measures such as strict requirements for migrant workers to drive motorcycles with licences, prohibit drunk driving, greater publicity of road safety regulations, and combining compulsory education with punishment for illegal behaviours.

Analysis of road traffic accidents and casualties associated with electric bikes and bicycles in Guangzhou, China: A retrospective descriptive analysis

Introduction

Electric bicycles (e-bikes) and bicycles in large Chinese cities have recently witnessed substantial growth in ridership. According to related accident trends, this study analyzed characteristics and spatial distribution in the period when e-bike-related accidents rapidly increased to propose priority measures to reduce accident casualties.

Methods

For e-bike- and bicycle-related accident data from the Guangzhou Public Security Traffic Management Integrated System, linear regression was used to examine the trends in the number of accidents and age-adjusted road traffic casualties from 2011 to 2021. Then, for the period when e-bike-related accidents rapidly increased, descriptive statistics were computed regarding rider characteristics, illegal behaviors, road types, collision objects and their accident liability. One-way analysis of variance (ANOVA) followed by Bonferroni's multiple comparison test. P < 0.05 was considered statistically significant. Finally, the density distribution of accidents was presented, and Moran's I (MI) was used for assessing spatial autocorrelation. Hotspots were identified based on an optimized hotspot analysis tool.

Results

Between 2011 and 2021, the number of accidents and casualty rate (per 100,000 population) increased for e-bikes but decreased for bicycles. After 2018, e-bike-related accidents increased rapidly, and bicycle-related accidents plateaued. Accident hotspots were concentrated in central city areas and suburban areas close to the former. Three-quarters of accidents occurred in motorized vehicle lanes. Most occurred on roads without physically segregated nonmotorized vehicle lanes. More than three-fifths of the accidents involved motor vehicles with at least four wheels. The prevalence (per 100 people) of casualties among e-bike rider victims and cyclist victims accounted for 92.0 % and 96.5 %, respectively. A total of 71.6 % of e-bike-related accidents involved migrant workers. Riding in motorized vehicle lanes was the most common illegal behavior.

Conclusions

Although e-bike-related and bicycle-related accidents presented similar characteristics, the sharp increase in e-bike-related accidents requires attention. To improve e-bike safety, governments should develop appropriate countermeasures to prevent riders from riding on motorways, such as improving road infrastructure, adjusting the driver's license system and addressing priority control areas.

Proposing a framework for evidence-based road safety policy-making: Connecting crash causation, countermeasures and policy

Effective evidence-based policy making within road safety is a several step cyclic process that involves gathering data about the causes of crashes, analysing these data, developing countermeasures and implementing and evaluating them. There are many examples of crash causation focused data collection activities available to policy makers but knowledge on how these finding may have led to countermeasure implementation and new policy is much less well established. This paper proposes a framework for best practice evidence-based policy making. To address existing gaps, the framework consists of three pillars: these are (1) Crash causation establishment; (2) Countermeasure development and implementation; and (3) road safety management. A key element in this framework is the recommendation for the establishment of an organisation responsible for road safety that has a strategic and coordination role. This framework, as a whole, aims to provide a practical high-level map by connecting evidence to policy at every point in the policy making cycle and ensuring that evidence-based road safety policy is a national priority. It is anticipated that using this framework to inform road safety policy development will enhance the success of any developed policy.

Nationwide Analysis of Motorcycle-Associated Injuries and Fatalities in the United States: Insufficient Prevention Policies or Abandoned Laws?

BACKGROUND

Motorcycle road traffic collisions are a major cause of mortality in the United States. We aimed to analyze the temporal and statewide trends in motorcycle collision fatalities (MCFs) nationwide and their association with state laws regarding motorcycle helmet requirements, lane splitting, speeding, intoxicating driving, and red light cameras.

METHODS

A retrospective review of United States MCF/capita from 2015 to 2019 was performed using the Fatality Analysis Reporting System database. MCF/capita was defined as a motorcyclist death per 100 000 motorcyclist registrations. Independent-samples t-test and ANOVA were used to determine differences, with significance defined as P < .05. Linear regression analysis and Pearson's correlation were used to further determine associations between variables.

RESULTS

The majority of fatalities occurred in males (n = 21 354, 91.0%), ages 25-54 (n = 13 728, 58.5%), and Caucasians (n = 19 195, 81.8%). A total of 24 states and DC exhibited positive trends in MCF/capita from 2015 to 2019. There was no significant difference in MCF/capita between states who had mandatory helmet laws for all, partial requirements, and states with no law (63.4 vs 54.3 vs 33.6, P = .360). Among fatalities involving alcohol, a significantly greater number of MCF/capita were found above the legal limit of .08 compared to the group with a blood alcohol concentration of .01-.07 (17.8 vs 4.5, P < .001).

CONCLUSION

Motorcyclist fatalities continue to pose a public health risk, with 24 states showing an upward trend. Additional interventions and laws are needed to decrease the number of motorcyclist deaths. Further strategy on implementation and enforcement of helmet laws and alcohol consumption may be an essential component.

Comparison of injury severity between E-bikes-related and other two-wheelers-related accidents: Based on an accident dataset

This study aims to compare the accident injury severity of e-bikes with that of other types of two-wheelers based on accident data and to analyze the factors influencing them. Using 1015 police accident records from Zhangjiakou City in 2020 and 2021, the accident injury severity of e-bikes was firstly compared with that of other two-wheelers based on five levels of accident injury severity classified according to the records. Two ordered Probit regression models were secondly used to compare the factors influencing the accident injury severity of e-bikes with that of other two-wheelers and the magnitude of their effects. At the same time, the contributions of each influential factor to the degree of accident injury of two-wheelers were estimated with the assistance of classification trees. Results show that e-bikes are closer to bicycles than motorcycles in terms of injury severities and the factors influencing them, in which the factors "accident configuration," "division of responsibility for the accident," and "collision with a heavy vehicle or four-wheeled vehicle" are significant. Based on the findings, potential measures are suggested to reduce e-bike accident casualties, such as improving rider education, ensuring speed limit enforcement, promoting safety equipment wearing, and making road design friendly to non-motorized and elderly riders. The results of this study can provide an essential reference for traffic management and rider education measures on e-bikes.

Stabbed by motorcycle? Reconstruction of an unusual traffic accident

The reconstruction of traffic accidents involving powered two-wheelers (PTWs) frequently proves to be a challenging task. A case in which a fatal head-on crash of a PTW with a small truck where only minor vehicles damage was observed but resulted in isolated fatal chest trauma is discussed here. External examination of the corpse revealed two lacerations on the back, at the first glance implying sharp trauma. Based on the accident traces, the technical expert assumed an emergency break of the PTW rider resulting in a rotation of the PTW in terms of a wheelie on the front wheel. The first contact between the PTW rider and the tail end of the small truck probably occurred with the upper side of the helmet, and then, the back handle of the PTW caused the stab-like injuries followed by compression of the rider between the small truck or asphalt and the PTW. Based on the few accident traces available, neither a reconstruction of the pre-impact velocity nor a detailed reconstruction of the PTW rider kinematics was possible. However, using an interdisciplinary approach, the principal collision position as well as the injury mechanisms could be reconstructed.

Risk of motorcycle collisions among patients with type 2 diabetes: a population-based cohort study with age and sex stratifications in Taiwan

AIMS

To investigate the overall and sex-age-specific absolute and relative risks of motorcycle collisions at road traffic accidents among patients with type 2 diabetes.

METHODS

A cohort study in Taiwan was conducted by following 989,495 patients with type 2 diabetes and the same number of matched controls recruited between 2010 and 2012 to the end of 2016. Collision events by motorcycle driver victims were identified from the Police-reported Traffic Accident Registry. Overall and sex-age-specific incidence rates of collision involving motorcycle driver victims were estimated under Poisson assumption. The Cox proportional hazard regression models were performed to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) of collision in association with type 2 diabetes.

RESULTS

Over an up to 7 years of follow-up, patients with type 2 diabetes had a higher incidence rate of motorcycle collision than controls at 1.16 and 0.89 per 100 person-years, respectively, which represented a significantly elevated HR of 1.28 (95% CI 1.27-1.30) after adjusting for potential confounders including various diabetic complications. The elevated HR was similarly seen in both men and women patients, and was significantly decreasing with increasing age regardless of sex. Little evidence supported the dose-response relationship between duration of type 2 diabetes and motorcycle collision risk.

CONCLUSIONS

After adjustment for common diabetic complications and comorbidities that could impair driving performance, patients with type 2 diabetes still suffered from increased risk of motorcycle collisions, regardless of sex, but was more evident in younger than in older patients.

The impacts of non-motorized traffic enforcement cameras on red light violations of cyclists at signalized intersections

INTRODUCTION

With a significant increase in accidents involving cyclists, more attention has been paid to cycling safety. Previous studies on traffic accident revealed that red-light violations of non-motorized vehicles have become the leading cause of crashes at signalized intersections. The objective of this study is to investigate the impact of non-motorized traffic enforcement cameras (NTECs) on the red-light running behavior of cyclists, including ordinary e-bike riders, delivery e-bike riders, and bicyclists.

METHOD

An observational study of 5,217 cyclists was conducted at six primary intersections in the downtown areas of Nanjing, China. A random parameter logit model was used to explore the safety effect of the NTECs and other factors related to red-light violation behavior.

RESULTS

The results indicate higher reductions in red-light violations at intersections with the NTECs compared than at the non-adjacent intersections without the NTECs. Furthermore, the NTECs demonstrated a beneficial but smaller impact on the reduction of violations at adjacent intersections. Another primary finding was that the effects of the NTECs varied among three types of cyclists (ordinary e-bike riders, delivery e-bike riders, and bicyclists).

CONCLUSIONS

The NTECs were found to be most effective in the case of delivery e-bike riders, followed by ordinary e-bike riders and bicyclists. In addition, the factors associated with the red-light violation behaviors of these three groups were also found to be different. In general, group size, maximum waiting time, waiting position, and visual search were significantly related to the probability of red-light violations in all three groups.

PRACTICAL APPLICATIONS

Based on these findings, this study provides some feasible suggestions for improving the effect of the NTECs and for the future extension of the NTECs installation, such as the randomization of the enforcement and publicity campaigns.

When the Helmet Is Not Enough: Forensic Multidisciplinary Reconstruction of a Deadly Motorcycle Accident

We report the case of a 54-year-old man who died in a motorcycle accident due to loss of control of the vehicle on a viaduct. No other vehicles were apparently involved, except for a car hit by the motorcycle after it fell. A post-mortem CT scan (computed tomography scan) was performed showing complex head trauma with a subarachnoid hemorrhage and multiple skull and facial bone fractures. A forensic cinematic reconstruction performed by an engineer was needed to exclude other incident causes other than the loss of control. The multidisciplinary approach that included autopsy findings, a cinematic reconstruction, a helmet test and an examination played a key role in clarifying the dynamics of the accident, allowing us to explain how the death occurred despite the motorcyclist’s helmet use. The cause of death was identified as a penetrating head trauma with cerebral material exposure, produced by the impact of the head against a fixed bolt in the guardrail base. Despite the use of the helmet, the impact force was enough to render the protection ineffective and allowed the bolt to penetrate through the helmet and the skull.

Modelling duration of car-bicycles overtaking manoeuvres on two-lane rural roads using naturalistic data

Nowadays, Spanish two-lane rural roads frequently accommodate sport cyclists. They usually ride on the shoulder or on the right edge of the lane, sharing the infrastructure with motorised vehicles. Due to the speed difference between road users, the most frequent and dangerous interaction is in overtaking manoeuvres. One key factor from a safety and traffic operation point of view is the overtaking duration. The main aim of this paper is to analyse how factors related to the road, the cyclists, and the overtaking manoeuvre influence the duration of overtaking to cyclists on two-lane rural roads. Naturalistic field data were obtained using instrumented bicycles. Seven groups of cyclists, formed by different numbers of cyclists riding in-line and two-abreast, rode along five rural roads with different geometric and traffic characteristics. A total of 1592 flying manoeuvres, in which drivers did not reduce their speed, and 192 accelerative manoeuvres were analysed. The overtaking duration, considering each overtaking strategy, was modelled using Bayesian statistics. Results showed that flying manoeuvres were more prevalent than accelerative. They were performed with higher speeds and lower lateral clearances and, therefore, presented lower overtaking durations. For both overtaking strategies, duration increased on wider roads and with a larger size of the group. The presence of an oncoming vehicle decreased the overtaking duration. However, other factors presented opposite effects on the duration depending on the overtaking strategy. The developed predictive models allow obtaining overtaking durations varying road and cyclist grouping characteristics. Results can be used by road administration to manage and propose some specific countermeasures to integrate the cyclists in a safe and efficient way on two-lane rural roads.

Risky behaviors, psychological failures and kinematics in vehicle-to-powered two-wheeler accidents: Results from in-depth Chinese crash data

As the use of powered two-wheeler (PTW) becomes increasingly prevalent, PTW accidents are emerging as a major threat to the people's life and property in China. Understanding the risky behaviors, psychological failures and kinematics in vehicle-to-PTW accidents is an important first step in addressing this issue. Here 69 vehicle-to-PTW accidents captured on video from the Traffic Accident Investigation and Research in China (TAIRC) database are selected and reconstructed. All accidents are categorized into different crash scenarios using a harmonized method. Accident causations are identified from the perspectives of praxeology and psychology. Kinematics characteristics, such as impact speed and relative position, are also analyzed. The results show the crossing accident bundle is the most frequent followed by rear, oncoming and run-up accident bundles, with proportions of 43.48 %, 27.54 %, 11.59 % and 17.39 % respectively. Accident causations of different crash scenarios have great differences whether in accident responsibilities or in psychological failures. For instance, the PTW riders who violate the traffic regulations need to be mainly responsible for most crossing accidents, whereas most rear accidents are blamed on drivers who fail to properly check their mirrors when they turn, turn around or change lanes. From the perspective of psychology, the perception failures encountered by both drivers and riders are a typical causation in crossing accidents, while it is a contributing factor in rear accidents that a failure of prognosis from the rider combined with a failure of perception from the driver. Visual obstruction exists widely in crossing and oncoming accident bundles. The impact speeds of vehicles and PTWs are often less than 40 km/h in all accident bundles. A wider sensing area (field of view = 90°, view detection range = 35 m) should be achieved to more effectively detect the conflict PTWs. These findings about vehicle-PTW accidents provide a stronger support for the development of prevention countermeasures and advanced driver assistance system.