Pedestrian Injuries Research Articles

Critical patterns associated with vehicle-pedestrian hit-and-run casualty injury severity under different weather conditions: An association rule mining approach

Vehicle-pedestrian hit-and-run crashes have grave consequences as the pedestrian casualty is left at the crash scene, leading to delays in emergency response. Research indicates that prevailing weather conditions are pivotal in influencing these crashes. Nonetheless, there exists a substantial gap in understanding the diverse associations of contributing factors that impact the severity of pedestrian injuries in vehicle-pedestrian hit-and-run crashes under varying weather conditions. This paper extensively examines the intricate patterns of critical factor associations influencing the pedestrian casualty injury severity in vehicle-pedestrian hit-and-run collisions in Ghana, differentiating between clear and inclement weather conditions. Leveraging historical crash data, this research employs the robust Association Rule Mining tool to unveil the relationships between key crash factors and their outcomes. The association rules extracted from the data reveal that specific factors consistently influence injury outcomes in vehicle-pedestrian hit-and-run crashes, regardless of weather conditions. However, there are distinct patterns of factors contributing to fatal and severe injuries in these crashes that vary depending on the prevailing weather conditions. Hit-and-run crashes resulting in fatal and severe pedestrian injuries are primarily associated with males and are notably correlated with factors like pedestrian crossings, late and early morning hours, the absence of traffic control measures on median-separated motorways, and good urban roads, regardless of prevailing weather conditions. During clear weather conditions, fatal/severe injuries tend to occur in daylight conditions, primarily on roadways devoid of shoulders, and involve older pedestrians crossing the road. Conversely, for inclement weather conditions, these crashes are more prone to occur during nighttime hours on unlit roads, often involving younger pedestrians walking along the road's edge. The reduction of fatal/severe injury hit-and-run crashes involving vehicles and pedestrians can be effectively tackled by eliminating or improving the critical factors pinpointed in the extracted rules. The study underscores the urgency of policy recommendations to mitigate fatalities resulting from vehicle-pedestrian hit-and-run crashes, emphasising the need for stricter legislation, heightened enforcement measures, increased awareness of pedestrian safety, enhanced driver training, and infrastructure upgrades. By acting on these insights, a significant stride can be made in curbing the alarming rates of vehicle-pedestrian hit-and-run fatalities.

Injury characteristics and mortality in an emergency department in Ethiopia: a single-center observational study

IntroductionAn injury is described as any damage to the body that impairs health, and its severity can span from mild to life-threatening. On a global scale, injuries account for approximately 4.4 million deaths annually and are anticipated to become the seventh leading cause of death by 2030. In Ethiopia, injuries account for 7% of all deaths, with one of the world's highest rates of road traffic injuries. This study, undertaken at a primary trauma centre in the capital of Ethiopia, aimed to explore the characteristics of injured patients and emergency department mortality as the patient outcome. Understanding the patterns and outcomes of injuries helps to anticipate needs, prioritize patients, and allocate resources effectively.MethodsA retrospective single-center observational study utilised patient records from September 2020 to August 2021 at Addis Ababa Burn Emergency and Trauma Hospital, located in Ethiopia. A structured checklist facilitated the data collection. All patients arriving in the ED from September 2020 to August 2021 were eligible for the study while incomplete records (missing > 20% of wanted data elements) were excluded.ResultOf the 3502 injured patients recorded during the study period, 317 were selected. The mean patient age was 30 years, with 78.5% being male. About 8% arrived the emergency department within an hour after the injury. Ambulances transported 38.8% of patients; 58.5% of these were referred from other facilities. The predominant mechanism of injury both in and outside Addis Ababa was pedestrian road traffic injuries (31.4% and 38%). The predominant injury type was fractures (33.8%). The mortality rate was 5%, of which half were pedestrian road traffic incidents.ConclusionPedestrian road traffic injuries were the main cause of injury in and outside of Addis Ababa. A small proportion of patients arrived at the emergency department within the first hour after an injury event. A significant proportion of ambulance-transported patients were referred from other facilities rather than directly from the scene. The overall mortality rate was high, with pedestrian road traffic injury accounting for half of the proportion.

Pedestrian wintertime slip and fall injuries-effectiveness of weather warning service in prevention.

In climates with wintry conditions, slip and fall injuries of pedestrians during wintertime can result in high healthcare and societal costs. The aim of this study was to evaluate the effectiveness of early warnings about slipperiness in preventing such injuries in Finland. Since 2004, the Finnish Meteorological Institute (FMI) has been providing a weather service for pedestrians, which has been developed continuously over time. Time series of pedestrian slip and fall injuries in commuting on foot in the 19 regions of Finland in 2005-2022 was obtained from the Finnish Workers' Compensation Center and analysed for trends. We also analysed daily warnings about slippery sidewalks from the FMI archives for the period 2011-2022. To identify steps in the service chain that require improvement, we conducted a weather service chain analysis (WSCA) based on a slip and fall accident storyline. There was no significant trend in the number of slipping injuries during the study period. The exposure of the Finnish population to slippery conditions varies according to the climate of the region and characteristics of the winters. We found that the responses of the users of the warning information may be inadequate. Changes in the behaviour of individuals and more efficient winter maintenance of sidewalks are required. Furthermore, it is necessary to promote the role and safety of walking in the planning of traffic systems and urban planning. Further improvements to the pedestrian weather service are needed as well.

Injury patterns in motor vehicle collision–youth pedestrian deaths

Objective The objective of this study was to describe fatal pedestrian injury patterns in youth aged 15 to 24 years old and correlate them with motor vehicle collision (MVC) dynamics and pedestrian kinematics using data from medicolegal death investigations of MVCs occurring in the current Canadian motor vehicle (MV) fleet. Methods Based on a systematic literature review, MVC–pedestrian injuries were collated in an injury data collection form (IDCF). The IDCF was coded using the Abbreviated Injury Scale (AIS) 2015 revision. The AIS of the most frequent severe injury was noted for individual body regions. The Maximum AIS (MAIS) was used to define the most severe injury to the body overall and by body regions (MAISBR). This study focused on serious to maximal injuries (AIS 3–6) that had an increasing likelihood of causing death. The IDCF was used to extract collision and injury data from the Office of the Chief Coroner for Ontario (OCCO) database of postmortem examinations done at the Provincial Forensic Pathology Unit (PFPU) in Toronto, Canada, and other provincial facilities between 2013 and 2019. Injury data were correlated with data about the MVs and MV dynamics and pedestrian kinematics. The study was approved by the Western University Health Science Research Ethics Board (Project ID: 113440; Lawson Health Research Institute Approval No. R-19-066). Results There were 88 youth, including 54 (61.4%) males and 34 (38.6%) females. Youth pedestrians comprised 13.1% (88/670) of all autopsied pedestrians. Cars (n = 25/88, 28.4%) were the most frequent type of vehicle in single-vehicle impacts, but collectively vehicles with high hood edges (i.e., greater distance between the ground and hood edge) were in the majority. Forward projection (n = 34/88, 38.6%) was the most frequent type of pedestrian kinematics. Regardless of the type of vehicle, there was a tendency in most cases for the median MAISBR ≥ 3 to involve the head and thorax. A similar trend was seen in most of the pedestrian kinematics involving the various frontal impacts. Of the 88 cases, at least 63 (71.6%) were known to be engaged in risk-taking behaviors (e.g., activity on roadway). At least 12 deaths were nonaccidental (8 suicides and 4 homicides). Some activities may have been impairment related, because 26/63 (41.3%) pedestrians undertaking risk-taking behavior on the roadway were impaired. Toxicological analyses revealed that over half of the cases (47/88, 53.4%) tested positive for a drug that could have affected behavior. Ethanol was the most common. Thirty-one had positive blood results. Conclusion A fatal dyad of head and thorax trauma was observed for pedestrians struck by cars. For those pedestrians hit by vehicles with high hood edges, which were involved in the majority of cases, a fatal triad of injuries to the head, thorax, and abdomen/retroperitoneum was observed. Most deaths occurred from frontal collisions and at speeds more than 35 km/h.

Unveiling the determinants of injury severities across age groups and time: A deep dive into the unobserved heterogeneity among pedestrian crashes

Pedestrians, particularly susceptible to road traffic crashes, experience varying injury severities influenced by age and time shifts. This research aims to investigate the differences and temporal shifts in factors influencing pedestrian injury severities across different age groups. To achieve this, three random parameters binary logit models with heterogeneity in the means (and variances) were employed. Four years of pedestrian crash data in Hong Kong were utilized in this study. According to United Nations’ definitions of the young and elderly, pedestrians were categorized into three groups: young (under 25 years old), middle-aged (25–65 years old), and elderly (over 65 years old). Initial likelihood ratio tests indicated temporal stability in the young group between 2019 and 2021, with further tests confirming age transferability and overall temporal stability after integrating the three years of young data. The partially constrained temporal stability approach was then developed to further capture the temporal stability of individual variables and simplify model results. Model results identified factors impacting pedestrian injury severities, encompassing pedestrian, driver, vehicle, temporal, and light condition characteristics. Some contributing variables exhibit age-transferability or temporal stability, such as controlled crossing, near controlled crossing, inattentive driver and private car. However, the significance of most contributors varies across age groups and years, with certain factors being age-specific or year-specific. Out-of-sample predictions underscore the cumulative likelihood of fatal or severe injuries with advancing age, and the middle-aged models showed the highest level of temporal stability regarding the risk of injury severity compared to the other two age models. Moreover, middle-aged pedestrians in Hong Kong faced the highest risk of fatal or severe injuries during the first year of the COVID-19 lockdown (2020), but the risk significantly declined for pedestrians of all age groups in the subsequent year. Based on these findings, targeted preventive measures that take into account age differences have been proposed to effectively enhance pedestrian safety.

Age, sex, sensation-seeking, and road-crossing: How does risk context impact children’s street-crossing?

Objective Child pedestrian injuries are a significant public health problem, largely because children have underdeveloped cognitive-perceptual capacity to judge traffic unsupervised. This study used a virtual reality (VR) environment to examine the impact of children’s age, as well as sex and sensation-seeking personality, on pedestrian behavior in different risk contexts. Methods 405 Norwegian children (7–10-year-olds) engaged in street-crossing scenarios within a VR environment. Children crossed a bicycle path and urban roadway six times, each with increasing density and complexity of traffic. Hits and near hits were recorded. Self-reported sensation-seeking personality was assessed. Results Children were more likely to experience crashes in the tasks that offered higher probability risk. Overall, 106 children crossed safely in all tasks. Dangerous crossings were associated with male sex, higher thrill and intensity seeking personality, and denser traffic. Age was not related to any traffic safety outcomes. Conclusion As expected, children were struck by vehicles more often in complex traffic contexts than in less complex ones. The results support previous findings and suggest that boys and sensation seekers have elevated risk of pedestrian injury, and that individual differences in children, rather than age alone, must be considered when determining if children are capable of safely negotiating traffic unsupervised.

Environmental measures to improve pedestrian safety in low- and middle-income countries: a scoping review.

This scoping study aims to identify environmental road safety measures implemented in low- and middle-income countries (LMICs) to reduce pedestrian injuries from collisions with motor vehicles. This review followed Arksey and O'Malley's approach and reported results using the PRISMA-SCR 2018 checklist. A literature review was conducted in Medline, Google Scholar, and the Transport Research International Documentation database using keyword-derived medical subject heading terms. A total of 14 articles met the pre-established inclusion criteria and were analyzed using a data extraction matrix. The findings were categorized methodically into three prominent themes: (1) methods for reducing pedestrian exposure, (2) traffic calming strategies, and (3) measures for enhancing pedestrian visibility. Traffic calming strategies, including vehicular speed reduction, roadway contraction, and vertical and horizontal diversionary tactics, emerged as the most effective interventions for reducing pedestrian injuries within LMICs. Conversely, interventions geared towards minimizing pedestrian exposure, such as zebra crossings, crosswalks controlled by traffic signals, underpasses, or overpasses, often produced minimal effects, and occasionally exacerbated the risk of pedestrian accidents. Lack of pedestrian visibility due to density of street vendors and parked vehicles was associated with a higher risk of injuries, while billboards impaired drivers' attention and increased the likelihood of collisions with pedestrians. In LMICs, the effectiveness of environmental measures in reducing vehicle-pedestrian crashes varies widely. In the face of resource constraints, implementing interventions for pedestrian safety in LMICs necessitates careful prioritization and consideration of the local context.

Children’s ability to estimate approaching vehicle time-to-arrival following training in a virtual pedestrian environment

Objectives Child pedestrian injuries represent a significant public health challenge. Understanding the most complex cognitive skills required to cross streets helps us understand, improve, and protect children in traffic, as underdeveloped cognitive skill likely impacts children’s pedestrian safety. One complex component of street-crossing is the cognitive-perceptual task of judging time-to-arrival of oncoming traffic. We examined capacity of 7- and 8-year-olds to judge time-to-arrival for vehicles approaching from varying distances and speeds, as well as improvement in those judgments following intensive street-crossing training in a virtual reality (VR) pedestrian simulator. Methods 500 seven- and eight-year-olds participated in a randomized trial evaluating use of a large kiosk VR versus smartphone-based VR headset to teach street-crossing skills. Prior to randomization into VR training condition and also prior to initiation of any training, children engaged in a video-based vehicle approach estimation task to assess ability to judge traffic time-to-arrival. They then engaged in multiple VR-based pedestrian safety training sessions in their randomly assigned condition until achieving adult functioning. Soon after training and again 6 months later, children repeated the vehicle estimation task. Results Prior to randomization or training, children were more accurate judging time to arrival for closer versus farther traffic, and rapidly-moving versus slower-moving traffic, but those results were subsumed by a speed x distance interaction. The interaction suggested distance cues were used more prominently than speed cues, and speed had varying effects at different distances. Training group had minimal effect on learning and all children became significantly better at judging vehicle arrival times following training. Conclusions Children tend to underestimate vehicle arrival times. Distance cues are more impactful on time-to-arrival judgments than speed cues, but children’s estimations based both on manipulations of vehicle speed and manipulations of vehicle distance improved post-training. Improvements were retained six months later. This finding is consistent with psychophysics research suggesting vehicle approach judgments rely on optical size and looming, which are impacted both by vehicle speeds and distances. Implementation of VR-based training for child pedestrian safety is recommended, as it may improve children’s judgment of vehicle time-to-arrival, but it must be conducted cautiously to avoid iatrogenic effects.

Emergency Department Visits for Pedestrians Injured in Motor Vehicle Traffic Crashes - United States, January 2021-December 2023.

Traffic-related pedestrian deaths in the United States reached a 40-year high in 2021. Each year, pedestrians also suffer nonfatal traffic-related injuries requiring medical treatment. Near real-time emergency department visit data from CDC's National Syndromic Surveillance Program during January 2021-December 2023 indicated that among approximately 301 million visits identified, 137,325 involved a pedestrian injury (overall visit proportion=45.62 per 100,000 visits). The proportions of visits for pedestrian injury were 1.53-2.47 times as high among six racial and ethnic minority groups as that among non-Hispanic White persons. Compared with persons aged ≥65 years, proportions among those aged 15-24 and 25-34 years were 2.83 and 2.61 times as high, respectively. The visit proportion was 1.93 times as high among males as among females, and 1.21 times as high during September-November as during June-August. Timely pedestrian injury data can help collaborating federal, state, and local partners rapidly monitor trends, identify disparities, and implement strategies supporting the Safe System approach, a framework for preventing traffic injuries among all road users.

Different smartphone tasks and traffic complexity affect pedestrian awareness of co-existing road objects and cerebral oxygenation during shared space walking

Distraction, primarily owing to the widespread use of cell phones and mobile devices while walking, is a contributing factor to pedestrian injuries. Pedestrians distracted by smartphones exhibit decreased situational awareness, influenced by the nature of concurrent tasks. However, little is known about the neural correlations between smartphone use and pedestrian responses to safety–critical events in a walking environment. This study recruited 30 young adults to investigate pedestrians’ ability to selectively respond to road objects while using smartphones (texting and reading) while walking in an immersive virtual environment system. The level of traffic complexity for the road conditions was manipulated by varying the number of safety–critical road objects coexisting in the environment at any given time and the number of required responses to the number of objects. During each 7-min task condition, cerebral oxygenation was measured using functional near-infrared spectroscopy. Furthermore, smartphone task performance, response times to road objects, and perceived workload were also measured. The participants exhibited reduced texting speed and reading performance when responding sequentially to coexisting road objects. Compared with other road conditions, those requiring two responses to four objects resulted in an increased workload and longer object response times. Participants perceived a higher workload in conditions involving tasks with smartphones than those without smartphones. More importantly, increased concentrations of oxygenated hemoglobin in the prefrontal cortex were observed when participants were concurrently performing smartphone and pedestrian tasks. Compared to smartphone reading, smartphone texting induced greater cerebral oxygenation in the bilateral frontopolar cortex. These results suggest that continuously texting while walking may demand additional cognitive resources for executive function. The findings of this study represent an initial step towards elucidating the cognitive mechanisms underlying attentional impairments experienced during smartphone distraction and working towards a viable solution to mitigate pedestrian risk.

Pedestrian injury severities resulting from vehicle/pedestrian intersection crashes: An assessment of COVID-contributing temporal shifts

Pedestrian mobility has become an increasingly important concern in transportation system analysis because of its positive impacts on the environment and healthy lifestyles. However, pedestrian safety in a vehicle-dominated transportation network remains a concern and potential barrier to pedestrian mobility, with pedestrian intersection safety being of particular concern. In addition, it is important to understand how pedestrian safety has been affected by the COVID-19 pandemic, perhaps permanently shifting pedestrian injury risks. This research seeks to provide insight into how pedestrian injury risks at intersections have changed as a result of the pandemic by estimating a series pedestrian injury severity models. To do so, unconstrained and partially constrained random parameters multinomial logit models with heterogeneity in the means of random parameters were estimated. Using Florida data, two one-year periods (one year before and one year after the COVID-19 pandemic) were defined based on vehicle miles traveled. The sample includes 3,780 single pedestrian-single vehicle crashes (2,348 from daytime and 1,432 from nighttime). A broad range of variables was considered to assess how the parameters may have shifted between the before and after periods. A series of likelihood ratio tests were conducted to examine the stability of model parameter estimates across the predefined time periods as well as to determine the differences between the daytime and nighttime crash injury severity outcomes. The results show that the nighttime crashes experienced more temporal shifts relative to daytime crashes. The findings also showed that both pedestrian and driver behavior played key temporally-shifting roles before and after the COVID-19 pandemic period. Finally, the out-of-sample simulations suggest that pedestrian injuries have become more severe after the pandemic.

Injury and fatality risks for child pedestrians and cyclists on public roads

BackgroundPedestrians and cyclists are often referred to as “vulnerable road users,” yet most research is focused on fatal crashes. We used fatal and nonfatal crash data to examine risk factors (i.e., relationship to an intersection, urbanicity, crash circumstances, and vehicle type) for police-reported pedestrian and cyclist injuries on public roads among children aged 0–9 and aged 10–19. We also compared risk factors among these two age groups with adults aged 20–29 and aged 30–39.MethodsCrash data were obtained for 2016–2020 from the National Highway Traffic Safety Administration’s Fatality Analysis Reporting System for fatal crash injuries and Crash Report Sampling System for nonfatal crash injuries. We collected data on victim demographics, roadway, and vehicle- and driver-related factors. Descriptive analyses were conducted between and within pedestrian and cyclist victims.ResultsWe analyzed 206,429 pedestrian injuries (36% in children aged 0–19) and 148,828 cyclist injuries (41% in children aged 0–19) from 2016 to 2020. Overall, child pedestrians had lower injury rates than adults, but children aged 10–19 had greater cycling crash rates than adults. Almost half of the pedestrian injuries in children aged 0–9 were “dart-out” injuries (43%). In the majority of the cyclist injuries, children in both age groups failed to yield to vehicles (aged 0–9 = 40% and aged 10–19 = 24%). For children and all ages included in the study, the fatality risk ratio was highest when pedestrians and cyclists were struck by larger vehicles, such as trucks and buses. Further exploration of roadway factors is presented across ages and transportation mode.ConclusionOur findings on child, driver, vehicle, and roadway factors related to fatal and nonfatal pedestrian and cyclist injuries may help to tailor prevention efforts for younger and older children.

Roadside experiences of parents of children with developmental coordination disorder and/or attention deficit hyperactivity disorder.

Pedestrians are a vulnerable group at the roadside and previous research has identified that children with DCD and ADHD are at a heightened risk of pedestrian injuries. Despite this, limited research has explored parental perspectives of the pedestrian risks faced by children with DCD and/or ADHD. Understanding parents' perspectives provides a unique insight into the challenges children face every day and the concerns that parents perceive regarding their children's safety as pedestrians. Therefore, the aim of this study was to explore parents' perspectives of the pedestrian risks faced by their children with DCD and/or ADHD. Semi-structured interviews were conducted with 14 parents of primary school and early secondary school aged children with age range 7-17. The participants were divided into three groups based on their children's conditions: DCD group (10-17 years, n = 3), ADHD group (7-13 years, n = 5), and co-occurring group (7-16 years, n = 6). All parents confirmed an existing diagnosis and completed the SNAP-IV and DCDQ as screening tools. The interviews explored parents' perspectives regarding their children's pedestrian behaviors, parents' concerns and preventative measures taken to improve the pedestrian safety of their children with DCD and/or ADHD. Reflexive thematic analysis was undertaken to analyze the interviews, from which three themes were developed. The first theme related to the challenges experienced by children at the roadside; parents emphasized the significance of structured and controlled pedestrian crossing sites, underlining their preference for designated crossings as safer options due to their heightened perceptions of risk associated with other road-crossing locations. The second theme: parental concerns and influences on children's road safety referred to their children's performance and safety at the roadside, leading to increased monitoring and a more protective approach to road crossing. The third theme: road safety education related to various strategies parents implemented to mitigate risks, while balancing independence and prioritizing their safety. While there were commonalities in the challenges faced by children with DCD and/or ADHD at the roadside, there were also notable differences. Parents of children with DCD discussed challenges with spatial awareness and motor skills, whereas parents of children with ADHD discussed challenges with impulsivity and inattention. Parents of children with co-occurring DCD and ADHD described a complex interplay of these challenges. It is evident from the interviews that children with DCD and/or ADHD require a distinct approach to develop their pedestrian skills effectively and parents reported specific strategies they used to address the risks associated with their children's roadside behavior. Promoting pedestrian safety for children with DCD and/or ADHD necessitates collaboration among parents, schools and local authorities to implement comprehensive measures ensuring their safety. These findings contribute to understanding parental experiences and needs, providing valuable guidance for targeted interventions and policies to enhance the road safety of children with DCD and/or ADHD.

Road Traffic Injuries and the Built Environment in Bogotá, Colombia, 2015-2019: A Cross-Sectional Analysis.

Nine in 10 road traffic deaths occur in low- and middle-income countries (LMICs). Despite this disproportionate burden, few studies have examined built environment correlates of road traffic injury in these settings, including in Latin America. We examined road traffic collisions in Bogotá, Colombia, occurring between 2015 and 2019, and assessed the association between neighborhood-level built environment features and pedestrian injury and death. We used descriptive statistics to characterize all police-reported road traffic collisions that occurred in Bogotá between 2015 and 2019. Cluster detection was used to identify spatial clustering of pedestrian collisions. Adjusted multivariate Poisson regression models were fit to examine associations between several neighborhood-built environment features and rate of pedestrian road traffic injury and death. A total of 173,443 police-reported traffic collisions occurred in Bogotá between 2015 and 2019. Pedestrians made up about 25% of road traffic injuries and 50% of road traffic deaths in Bogotá between 2015 and 2019. Pedestrian collisions were spatially clustered in the southwestern region of Bogotá. Neighborhoods with more street trees (RR, 0.90; 95% CI, 0.82-0.98), traffic signals (0.89, 0.81-0.99), and bus stops (0.89, 0.82-0.97) were associated with lower pedestrian road traffic deaths. Neighborhoods with greater density of large roads were associated with higher pedestrian injury. Our findings highlight the potential for pedestrian-friendly infrastructure to promote safer interactions between pedestrians and motorists in Bogotá and in similar urban contexts globally.

Experimental Study on Shear Strength of Roof–Snow Interfaces for Prediction of Roof Snow Sliding

The sliding of roof snow may result in surcharges of snow load on lower roofs or the injury of pedestrians on the ground. It is therefore of great significance to study the mechanism of roof snow sliding, such that prevention or control measures can be developed to manage the risk. Considering four commonly used roofing materials, glass, steel, membrane, and concrete, two types of experiments were carried out in this study to possibly reveal the influence of roofing materials on the shear strength of the roof–snow interface: one is the critical angle tests where the angle at which the snow starts to slide off from the roof is tested, and the other is the shearing tests which aim to test the shear strength of the roof–snow interfaces at specific temperatures. The results showed that the critical angle for roof snow sliding, as well as the shear strength of the roof–snow interface for the four considered roofing materials, show a U-shape trend with the increase in surface roughness and that the shear strength of the roof–snow surface ranges from 0.15 kPa to 2 kPa for the cases considered, while the strength reaches its maximum at certain temperatures near −5 °C for a specific roofing material and snow thickness. These findings could be a useful reference for future experimental or simulation studies on roof snow sliding.

A method for generating case-specific vehicle models from a single-view vehicle image for accurate pedestrian injury reconstructions

Developing vehicle finite element (FE) models that match real accident-involved vehicles is challenging. This is related to the intricate variety of geometric features and components. The current study proposes a novel method to efficiently and accurately generate case-specific buck models for car-to-pedestrian simulations. To achieve this, we implemented the vehicle side-view images to detect the horizontal position and roundness of two wheels to rectify distortions and deviations and then extracted the mid-section profiles for comparative calculations against baseline vehicle models to obtain the transformation matrices. Based on the generic buck model which consists of six key components and corresponding matrices, the case-specific buck model was generated semi-automatically based on the transformation metrics. Utilizing this image-based method, a total of 12 vehicle models representing four vehicle categories including family car (FCR), Roadster (RDS), small Sport Utility Vehicle (SUV), and large SUV were generated for car-to-pedestrian collision FE simulations in this study. The pedestrian head trajectories, total contact forces, head injury criterion (HIC), and brain injury criterion (BrIC) were analyzed comparatively. We found that, even within the same vehicle category and initial conditions, the variation in wrap around distance (WAD) spans 84–165 mm, in HIC ranges from 98 to 336, and in BrIC fluctuates between 1.25 and 1.46. These findings highlight the significant influence of vehicle frontal shape and underscore the necessity of using case-specific vehicle models in crash simulations. The proposed method provides a new approach for further vehicle structure optimization aiming at reducing pedestrian head injury and increasing traffic safety.

Timing and causes of death to 1 year among children presenting to emergency departments.

A better characterization of deaths in children following emergency care is needed to inform timely interventions. This study aimed to describe the timing, location, and causes of death to 1 year among a cohort of injured and medically ill children. We conducted a retrospective cohort study of children <18 years requiring emergency care in six states from January 1, 2012, through December 31, 2017, with follow-up through December 31, 2018, for patients who were not discharged from the emergency department (ED). In this cohort, 1-year mortality, time to death within 1 year, and causes of death were assessed from ED, inpatient, and vital status records. There were 546,044 children during the 6-year period. The 1-year mortality rate was 2.2% (n = 1356) for injured children and 1.4% (n = 6687) for medically ill children. Matched death certificates were available for 861 (63.5%) of 1356 deaths in the injury cohort and for 4712 (70.5%) of 6687 deaths in the medical cohort. Among deaths in the injury cohort, 1274 (94.0%) occurred in the ED or hospital. The most common causes of death were motor vehicle collisions, firearm injuries, and pedestrian injuries. Among the 6687 deaths in the medical cohort, 5081 (76.0%) children died in the ED or hospital (primarily in the ED) and 1606 (24.0%) occurred after hospital discharge. The most common causes of death were sudden infant death syndrome, suffocation and drowning, and congenital conditions. The 1-year mortality of children presenting to an ED is 2.2% for injured children and 1.4% for medically ill children with most deaths occurring in the ED. Future interventional trials, quality improvement efforts, and health policy focused in the ED could have the potential to improve outcomes of pediatric patients.

The immediate effects of vision-zero corridor upgrades on pedestrian crashes in New York: A before-and-after spatial point process approach

The long-term effects of the Vision-Zero (VZ) approach in Scandinavia are well documented. In contrast, information regarding the immediate effects of VZ at the starting phase upon gradual implementation is scarce. Taking New York City as the case study, we analyzed both the local and global effects of the Vision-Zero gradual implementation on pedestrian crashes in the early stage of implementation starting from 2014. The data analysis comprised 8,165 pedestrian injury crashes. Using location data, the crashes were matched to VZ infrastructure improvement location, start and completion dates. The experimental design included a treatment and two types of control conditions, and we controlled for well-known covariates including traffic exposure, land use, and risk-prone areas. We estimated a Geyer Saturation model and kernel density function for modeling the effect of Vision-Zero on crash intensity and dispersion two years before and after the implementation of Vision-Zero. The results reveal a significant global decrease of 6.1 % (p = 0.004) in pedestrian crash incidence in the treated sections compared with the control group two years after the treatment, and a greater dispersion of pedestrian injuries following the policy implementation.

An evaluation of a Vision Zero traffic-calming intervention, an urban transportation safety policy

ABSTRACT Today over 40 major metropolitan areas in the United States have formally adopted a new “Vision Zero” road design framework to prioritize roadway safety and eliminate traffic-related fatalities. This policy framework diffused across much of Europe and, more recently, the United States. In 2019, the City of San Francisco, California, implemented a series of traffic-calming interventions designed to lower speeds on left-hand turns and thereby reduce severe pedestrian and bicyclist injuries. This study uses a quasi-experimental design to evaluate this innovation. Results show that these safety measures reduced speeds between 1.4 and 1.9 miles per hour and that these reductions were sustained for at least 1 year. A conservative cost-benefit analysis suggests that these interventions have a large, positive return on investment, and that they are justified for any intersection with 2.5 or more pedestrian- or cyclist-involved crashes over a 5-year window.

Evaluating the Effectiveness of Speed Cameras on Philadelphia’s Roosevelt Boulevard

This paper employs Bayesian negative binomial and Poisson models to examine the effectiveness of speed cameras at reducing crashes, injuries, and fatalities on and immediately around Roosevelt Boulevard, a particularly dangerous urban arterial in Philadelphia, PA. Camera installation also coincided with rapidly changing traffic safety outcomes throughout the summer after COVID-19 lockdowns and protests against police violence. To find the most appropriate control segments for our analysis, we use k-means clustering to identify the five most similar roadways. Compared with these roadways and other geographic controls, the treated sections of Roosevelt Boulevard experienced decreased crashes, injuries, and fatalities after camera installation. These decreases are on the high end of what is found in the academic literature on speed cameras. The findings for total crashes, traffic injuries, fatalities, and pedestrian injuries are statistically different from zero with a high degree of confidence. Differences in pedestrian fatalities are statistically different from zero with 90% confidence. Based on our findings, we recommend that the Commonwealth of Pennsylvania and City of Philadelphia extend and expand the automated speed enforcement pilot. Estimates of the economic benefits of reduced crashes substantially exceed the total fines paid by violators. Despite this positive safety effect, additional treatments will be required to make Roosevelt Boulevard substantially safer. The roadway still accounts for around 8% of all traffic fatalities in Philadelphia.