Pedestrian fatality and impact speed squared: Cloglog modeling from French national data

Epidemiology of head injuries in pedestrian-motor vehicle accidents

Despite efforts of many countries to improve pedestrian safety, international reports show an upward trend in pedestrian-motor vehicle accidents. Although the most common cause of death of pedestrians is head injuries, there is a lack of knowledge on the epidemiology and characteristics of head injury in terms of the Glasgow Outcome Scale to be used for prevention. However, this study aimed to determine the epidemiology of pedestrian-motor vehicle accidents, the characteristics of head injury, and differences in the Glasgow Outcome Scale in terms of gender. In this retrospective analytical study, the data of 917 eligible injured pedestrians were obtained from the two databases of the Trauma System and the Hospital Information System. The data were analyzed using SPSS software (Version 21). The mean age of all 917 injured pedestrians was 47.55 ± 19.47 years. Most of the injured pedestrians (42.10%) were in the age range of 41-69 years and 81.31% were male. Moreover, 83.07% did not have any acute lesions on the CT scan. The most common brain lesion was brain contusion (n = 33, 3.60%), subarachnoid hemorrhage (n = 33, 3.60%), and skull fracture (n = 29, 3.16%). Among all concurrent injuries, lower extremity/pelvic injuries were observed in 216 patients (23.56%). Outpatient treatment (n = 782, 85.27%), airway control/endotracheal intubation (n = 57, 6.22%), and resuscitation (n = 35, 3.82%) were the most applied treatments respectively. There were significant differences in the Glasgow Outcome Scale between men and women (P- value = 0. 012). The high rate of mortalities, disability, head injuries, contusion, subarachnoid hemorrhage, and skull fractures in pedestrians involved in MVAs emphasizes the need for developing and implementing prevention strategies including appropriate management and risk reduction. Male pedestrians were at higher risk of motor vehicle accidents and worse Glasgow Outcome Scale. The presented data identified the main types of pedestrian injuries and suggested the importance of adopting appropriate preventive strategies to achieve the most effective interventions for creating a safer community.

Investigating the behavior of pedestrians and related factors in northern Iran in 2021

Among all road users, pedestrian behavior is most unpredictable, and our knowledge of pedestrian behavior and compliance in northern Iran is limited. The aim of the study was to determine the self-reporting behavior of pedestrians and related factors in northern Iran in 2021. This cross-sectional study's research tool included demographic characteristics, social characteristics, and a pedestrian behavior questionnaire (PBS - 43 questions). Data collection was randomly performed in 30 different passages around Rasht (a city in the north of Iran). We used the Poisson regression model and statistical software STATA version 15 for data analysis. With increasing age, pedestrians showed better crossing behavior (p < 0.001, β = 0.202), and the behavior of female pedestrians was better than that of male pedestrians (p < 0.001, β -4.79). As pedestrians, those with private jobs had worse crossing behavior than others (p < 0.045, β = 9.380), and those pedestrians who mentioned they were motorcyclists before had worse crossing behavior than others (p < 0.045, β = 9.380). The findings of this study can be used to establish pedestrian safety and preventative planning. In behavior change intervention programs, it is best to target young male pedestrians aiming to walk to their workplace, a private business. In addition, the behavior of pedestrians whose predominant means of transportation is the motorcycle must be corrected. It is necessary to conduct information campaigns and educational programs for pedestrians with common high-risk behaviors, especially errors and violations.

Holistic pedestrian safety assessment for average males and females

Objective

An integrated assessment framework that enables holistic safety evaluations addressing vulnerable road users (VRU) is introduced and applied in the current study. The developed method enables consideration of both active and passive safety measures and distributions of real-world crash scenario parameters.

Methods

The likelihood of a specific virtual testing scenario occurring in real life has been derived from accident databases scaled to European level. Based on pre-crash simulations, it is determined how likely it is that scenarios could be avoided by a specific Autonomous Emergency Braking (AEB) system. For the unavoidable cases, probabilities for specific collision scenarios are determined, and the injury risk for these is determined, subsequently, from in-crash simulations with the VIVA+ Human Body Models combined with the created metamodel for an average male and female model. The integrated assessment framework was applied for the holistic assessment of car-related pedestrian protection using a generic car model to assess the safety benefits of a generic AEB system combined with current passive safety structures.

Results

In total, 61,914 virtual testing scenarios have been derived from the different car-pedestrian cases based on real-world crash scenario parameters. Considering the occurrence probability of the virtual testing scenarios, by implementing an AEB, a total crash risk reduction of 81.70% was achieved based on pre-crash simulations. It was shown that 50 in-crash simulations per load case are sufficient to create a metamodel for injury prediction. For the in-crash simulations with the generic vehicle, it was also shown that the injury risk can be reduced by implementing an AEB, as compared to the baseline scenarios. Moreover, as seen in the unavoidable cases, the injury risk for the average male and female is the same for brain injuries and femoral shaft fractures. The average male has a higher risk of skull fractures and fractures of more than three ribs compared to the average female. The average female has a higher risk of proximal femoral fractures than the average male.

Conclusions

A novel methodology was developed which allows for movement away from the exclusive use of standard-load case assessments, thus helping to bridge the gap between active and passive safety evaluations.

Macro-level literature analysis on pedestrian safety: Bibliometric overview, conceptual frames, and trends

Due to the high volume of documents in the pedestrian safety field, the current study conducts a systematic bibliometric analysis on the researches published before October 3, 2021, based on the science-mapping approach. Science mapping enables us to present a broad picture and comprehensive review of a significant number of documents using co-citation, bibliographic coupling, collaboration, and co-word analysis. To this end, a dataset of 6311 pedestrian safety papers was collected from the Web of Science Core Collection database. First, a descriptive analysis was carried out, covering whole yearly publications, most-cited papers, and most-productive authors, as well as sources, affiliations, and countries. In the next steps, science mapping was implemented to clarify the social, intellectual, and conceptual structures of pedestrian-safety research using the VOSviewer and Bibliometrix R-package tools. Remarkably, based on intellectual structure, pedestrian safety demonstrated an association with seven research areas: "Pedestrian crash frequency models", "Pedestrian injury severity crash models", "Traffic engineering measures in pedestrians' safety", "Global reports around pedestrian accident epidemiology", "Effect of age and gender on pedestrians' behavior", "Distraction of pedestrians", and "Pedestrian crowd dynamics and evacuation". Moreover, according to conceptual structure, five major research fronts were found to be relevant, namely "Collision avoidance and intelligent transportation systems (ITS)", "Epidemiological studies of pedestrian injury and prevention", "Pedestrian road crossing and behavioral factors", "Pedestrian flow simulation", and "Walkable environment and pedestrian safety". Finally, "autonomous vehicle", "pedestrian detection", and "collision avoidance" themes were identified as having the greatest centrality and development degrees in recent years.

Effect of Lane Narrowing Implemented on an Urban Dual Carriageway on Speed Reduction and Acoustic Environment

The on-going growth in the use of motor vehicles leads to a number of traffic safety problems. Therefore, various traffic calming measures are applied to increase traffic safety in built-up areas. Lane narrowing is one of the techniques used to influence the perception of drivers and make them slow down. With this in mind, the authors conducted traffic volume and speed counts before and after installation of the lane narrowing treatment, covering 100 passing vehicles, at an intersection between an urban dual carriageway and an estate street where over a dozen fatal accidents occurred in the recent years. Traffic noise was also measured, both before and after lane narrowing. The traffic count data were analysed to show speed reduction by ca. 15 km/h, yet in all cases still above 50 km/h, which is the speed limit applicable to built-up areas in Poland. The analysis of the “before” and “after” noise maps showed only minor changes to the distribution of noise. The locations of these changes to the acoustic environment depended on the speed and volume of traffic and, much more importantly, on the topography of the surrounding area, the existing roadside layered landscape and the type of planted vegetation. The detailed analyses of the analysed parameters demonstrated that sustainable design of traffic calming measures on urban dual carriageways must consider not only the desired speed reduction but also the surrounding landscape and the local topography.

Factors Influencing Fatalities or Severe Injuries to Pedestrians Lying on the Road in Japan: Nationwide Police Database Study

To help reduce the number of pedestrians lying on the road suffering fatal or severe injuries as a result of vehicle collisions, we investigated the influencing factors. We conducted an analysis of the records of the Institute for Traffic Accident Research and Data Analysis Japan between 2012 and 2018; we found that 2452 pedestrians lying on the road were involved in collisions (797 fatalities, 784 severely injured, 871 mildly injured). Multivariate logistic regression analysis identified the following as major factors that positively influenced the fatalities: head or neck injuries (odds ratio [OR], 90.221); trunk injuries (OR, 71.040); trucks as offending vehicle (OR, 2.741); collision velocity of 10–20 km/h (OR, 31.794), 20–30 km/h (OR, 2.982), 30–40 km/h (OR, 8.394), 40–50 km/h (OR, 16.831), and >50 km/h (OR, 18.639); and hit-and-run cases (OR, 1.967). The following had a positive influence on severe injuries: trunk injuries (OR, 4.060); collision velocity of 10–20 km/h (OR, 2.540), 20–30 km/h (OR, 3.700), 30–40 km/h (OR, 5.297), 40–50 km/h (OR, 5.719), and ≥50 km/h (OR, 5.244); and hit-and-run cases (OR, 2.628). Decreasing the collision velocity, avoiding collisions to the head and neck or trunk, and preventing hit-and-run cases would be effective in reducing fatal or severe injuries to pedestrians lying on the road.

Evaluating the impact of Road Rangers in preventing secondary crashes

Many transportation agencies utilize freeway service patrols (FSPs) to quickly identify and respond to incidents. The objectives of FSP are to minimize the incident duration and increase safety at the incident scene. The current research explored the safety benefits of Florida's FSP program known as Road Rangers - harnessed from lowering the likelihood of secondary crashes (SCs) - compared to other responding agencies. The analysis was done on 6088 incidents that occurred on freeways in Jacksonville, Florida, from 2015 through 2017. Since SCs were not explicitly identified in the SunGuide® incident database, the study adopted a data-driven technique that used BlueToad® speed data to identify them. Once SCs were identified, a model was developed to identify factors influencing their occurrence. Factors such as an increase in equivalent hourly traffic volume, incident impact duration, and the percent of lanes closed significantly increased the likelihood of a SC. Besides, moderate/severe incidents, crash events, weekdays, peak hours, shoulder blockage, and incidents involving towing showed a high likelihood of resulting in a SC. Of practical importance, the model results revealed that a minute increase in incident impact duration increased the SC probability by 1.2 percent, with other factors held constant. Based on a 16-minutes decrease in incident impact duration, the Road Rangers program could lessen the probability of SCs by 21 percent, compared to other agencies. These findings could be beneficial to incident managers, responders, and researchers in evaluating the program's performance.

A state-of-the-art review of factors that predict mortality among traumatic injury patients following a road traffic crash

BACKGROUND

Traffic related injuries are a major public health problem worldwide with millions of people dying every year. The objective of this state-of-the-art review was to identify the factors reported in the literature as being associated with mortality for trauma patients following road traffic crashes.

METHOD

A systematic search was undertaken of PubMed/MEDLINE, EMBASE, CINAHL, Web of Science, and Cochrane Library databases to identify articles published in the past two decades (2000-2020). Of 8257 records, 4507 remained for title, abstract and full text screening after duplicates were removed. The level of evidence of selected studies was assessed using The National Health and Medical Research Council (NHMRC) guideline.

RESULTS

This review included eighty primary research studies examining mortality risk factors following a road traffic crash. The study identified factors in five categories; (i) demographic factors; (ii) behavioural factors; (iii) crash characteristics; (iv) environmental and timing factors; (v) injury severity and pre-injury/condition. The primary studies are summarised in a matrix. Included studies included level II to level IV levels of evidence based on the NHMRC criteria.

CONCLUSION

This study shows that there are a large number of factors associated with increased risk of mortality following diverse types of traffic crashes. Understanding these wide-ranging factors can strengthen injury and mortality prevention by guiding decision makers about where to focus strategy implementation.

Modeling Road Safety in Car-Dependent Cities: Case of Jeddah City, Saudi Arabia

Investigating the connections between pedestrian crashes and various urban variables is critical to ameliorate the prediction of pedestrian fatalities, formulate advisories for the stakeholders, and provide an evidence base for policy change to mitigate the occurrence and intensity of pedestrian fatalities. In this paper, we aim to explore the geographically varying association between the pedestrian fatalities and other associated factors of an urban environment in Jeddah city, which is a car-dependent city in Saudi Arabia. At first, Global Moran’s I and Local Indicators of Spatial Association (LISA) were applied to visualize the clustering of pedestrian fatalities in the various districts of Jeddah. Subsequently, we developed Poisson regression models based on their geographically weighted indicators. Both the global and geographically weighted regression models attempt to assess the association between the pedestrian fatalities and the geographically relevant land use and transport infrastructure factors. The results indicate that geographically weighted Poisson regression (GWPR) performed better than the global Poisson counterparts. It is also revealed that the existing transportation infrastructure in Jeddah was significantly associated with the higher pedestrian fatalities. The results have shown that the proposed model in this study can inform transport policies in Jeddah in prioritizing more safety measures for the pedestrians, including expanding pedestrians’ infrastructure, and cautious monitoring of pedestrian footpaths. It can facilitate the analysis and improvement of road safety for pedestrians in car-dependent cities.

Ethical Decision Making in Autonomous Vehicles: The AV Ethics Project

The ethics of autonomous vehicles (AV) has received a great amount of attention in recent years, specifically in regard to their decisional policies in accident situations in which human harm is a likely consequence. Starting from the assumption that human harm is unavoidable, many authors have developed differing accounts of what morality requires in these situations. In this article, a strategy for AV decision-making is proposed, the Ethical Valence Theory, which paints AV decision-making as a type of claim mitigation: different road users hold different moral claims on the vehicle's behavior, and the vehicle must mitigate these claims as it makes decisions about its environment. Using the context of autonomous vehicles, the harm produced by an action and the uncertainties connected to it are quantified and accounted for through deliberation, resulting in an ethical implementation coherent with reality. The goal of this approach is not to define how moral theory requires vehicles to behave, but rather to provide a computational approach that is flexible enough to accommodate a number of 'moral positions' concerning what morality demands and what road users may expect, offering an evaluation tool for the social acceptability of an autonomous vehicle's ethical decision making.

Effect of reducing the posted speed limit to 30 km per hour on pedestrian motor vehicle collisions in Toronto, Canada - a quasi experimental, pre-post study

Background

Pedestrian related deaths have recently been on the rise in Canada. The effect of changing posted speeds on the frequency and severity of pedestrian motor vehicle collisions (PMVC) is not well studied using controlled quasi-experimental designs. The objective of this study was to examine the effect of lowering speed limits from 40 km/h to 30 km/h on PMVC on local roads in Toronto, Canada.

Methods

A 30 km/h speed limit on local roads in Toronto was implemented between January 2015 and December 2016. Streets that remained at a 40 km/h speed limit throughout the study period were selected as comparators. A quasi-experimental, pre-post study with a comparator group was used to evaluate the effect of the intervention on PMVC rates before and after the speed limit change using repeated measures Poisson regression. PMVC data were obtained from police reports for a minimum of two years pre- and post-intervention (2013 to 2018).

Results

Speed limit reductions from 40 km/h to 30 km/h were associated with a 28% decrease in the PMVC incidence rate in the City of Toronto (IRR = 0.72, 95% CI: 0.58–0.89). A non-significant 7% decrease in PMVC incidence rates were observed on comparator streets that remained at 40 km/h speed limits (IRR = 0.93, 95% CI: 0.70–1.25). Speed limit reduction also influenced injury severity, with a significant 67% decrease in major and fatal injuries in the post intervention period on streets with speed limit reductions (IRR = 0.33, 95% CI: 0.13–0.85) compared with a 31% not statistically significant decrease in major and fatal injuries on comparator streets (IRR = 0.69, 95% CI: 0.37–1.31). The interaction term for group and pre-post comparisons was not statistically significant (p = 0.14) indicating that there was no evidence to suggest a pre-post difference in IRRs between the intervention and comparator streets.

Conclusions

Declines in the rate of PMVC were observed on roads with posted speed limit reductions from 40 km/h to 30 km/h, although this effect was not statistically greater than reductions on comparator streets.

Spatial analysis of traffic accidents involving older adults in a city in the northeast of Brazil

Abstract Objective: to describe the epidemiological characteristics of traffic accidents involving older victims, responded to by the Mobile Emergency Service (or SAMU), and to analyze the spatial distribution of these events in the city of Olinda, Pernambuco, Brazil, from 2015 to 2018. Method: a composite cross-sectional study was performed, using SAMU service records as a data source. Descriptive statistics were applied, based on frequency distribution. For the mapping and detection of spatial clusters, the Kernel intensity estimator was used. Results: SAMU responded to 137 traffic accidents with older victims. The most affected age group were older adults aged 60 to 69 years (81; 59.1%), and there was a predominance of male victims (90; 65.7%). The day of the week when most accidents occurred was Wednesday (29; 21.25%), and the highest number of accidents occurred in the morning (46; 33.6%). As for the nature of the accident, accidents involving pedestrians (80; 58.4) predominated over collisions (57; 41.6%). The Kernel intensity estimator identified a significant focus in the Peixinhos neighborhood, with other foci distributed throughout the coastal area. Conclusion: the study identified the characteristics of older victims of traffic accidents and areas of greatest risk for their occurrence in the city studied. This information can be useful when planning environmental engineering measures to be carried out in the regions identified, in order to reduce the frequency of accidents and injuries.

The relationship between impact speed and the probability of pedestrian fatality during a vehicle-pedestrian crash: A systematic review and meta-analysis

BACKGROUND

Pedestrians struck in motorised vehicle crashes constitute the largest group of traffic fatalities worldwide. Excessive speed is the primary contributory factor in such crashes. The relationship between estimated impact speed and the risk of a pedestrian fatality has generated much debate concerning what should be a safe maximum speed limit for vehicles in high pedestrian active areas.

METHODS

Four electronic databases (MEDLINE, EMBASE, COMPENDEX, and SCOPUS) were searched to identify relevant studies. Records were assessed, and data retrieved independently by two authors in adherence with the PRISMA statement. The included studies reported data on pedestrian fatalities from motorised vehicle crashes with known estimated impact speed. Summary odds ratios (OR) were obtained using meta-regression models. Time trends and publication bias were assessed.

RESULTS

Fifty-five studies were identified for a full-text assessment, 27 met inclusion criteria, and 20 were included in a meta-analysis. The analyses found that when the estimated impact speed increases by 1 km/h, the odds of a pedestrian fatality increases on average by 11% (OR = 1.11, 95% CI: 1.10-1.12). The risk of a fatality reaches 5% at an estimated impact speed of 30 km/h, 10% at 37 km/h, 50% at 59 km/h, 75% at 69 km/h and 90% at 80 km/h. Evidence of publication bias and time trend bias among included studies were found.

CONCLUSIONS

The results of the meta-analysis support setting speed limits of 30-40 km/h for high pedestrian active areas. These speed limits are commonly used by best practice countries that have the lowest road fatality rates and that practice a Safe System Approach to road safety.

Likelihood estimation of secondary crashes using Bayesian complementary log-log model

Secondary crashes (SCs) occur within the spatial and temporal impact range of a primary incident. They are non-recurring events and are major contributors to increased traffic delay, and reduced safety, particularly in urban areas. However, the limited knowledge on the nature of SCs has largely impeded their mitigation strategies. The primary objective of this study was to develop a reliable SC risk prediction model using real-time traffic flow conditions. The study data were collected on a 35-mile I-95 freeway section for three years in Jacksonville, Florida. SCs were identified based on travel speed data archived by the Bluetooth detectors. Bayesian random effect complementary log-log model was used to link the probability of SCs with real-time traffic flow characteristics, primary incident characteristics, environmental conditions, and geometric characteristics. Random forests technique was used to select the important variables. The results indicated that the following variables significantly affect the likelihood of SCs: average occupancy, incident severity, percent of lanes closed, incident type, incident clearance duration, incident impact duration, and incident occurrence time. The study results have the potential to proactively prevent SCs.

Epidemiology and Outcome Determinants of Pedestrian Injuries in a Level I Trauma Center in Southern Iran; A Cross-Sectional Study

Objective

To epidemiologically assess the accidents and incidents in the injured pedestrians referred to Shahid Rajaee Hospital, Shiraz in order to provide basic preventive strategies and reduce injuries and fatalities caused by traffic accidents in pedestrians.

Methods

This cross-sectional study was conducted on 5840 injured pedestrians referred to Shahid Rajaee Hospital, Shiraz from 2009 to 2014. The baseline characteristic including the demographic and clinical information, the mechanism of injury, injury severity score (ISS) and outcome determinants. We also recorded the outcome measures and the mortality. Multivariate logistic regression analysis was performed to investigate the factors related to mortality rate and Length of Stay (LOS) in hospital.

Results

In our study, the history of 5840 injured pedestrians was analyzed. The mean age of the patients was 41.32 ± 19.21 years. Multivariate logistic regression indicated that mortality increased with age. Moreover, the odds of mortality was more in patients with Injury Severity Score (ISS) between 16 and 24 [OR: 12.94, 95% CI (3.78-32.66), p=0.001] and injuries in the head and neck [OR: 7.92, 95% CI (4.18-14.99), p=0.020]. LOS in hospital was also higher in patients with ISS > 25 [OR: 16.65, 95%CI (10.68-25.96), p=0.001].

Conclusion

Pedestrians have always been one of the most vulnerable road users. Our study indicated that the adverse consequences and mortalities in pedestrians increased with age. Hence, approaches are required to improve primary prevention programs and reduce deaths and injuries due to this major public health problem.