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.

Factors affecting driver injury severity in fatigue and drowsiness accidents: a data mining framework.

BACKGROUND: Fatigue and drowsiness accidents are more likely to cause serious injuries and fatalities than other accidents. Statistics revealed that 20 to 40 percent of traffic accidents in Iran are due to drivers' fatigue. This study identified the most important factors affecting driver injuries in fatigue and drowsiness accidents. METHODS: The Classification and Regression Tree method (CART) was applied 11,392 drivers were in-volved in fatigue and drowsiness accidents in three provinces of Iran, over the 7 years from 2011-2018. A two-level target variable was used to increase the accuracy of the model. First, dataset in each of three provinces was classified into homogeneous clusters using a two-step clus-tering algorithm. Oversampling method was used for imbalanced accident severity datasets. Then, classification was improved by boosting method. RESULTS: The classification tree reveals that the month, time of day, collision type, and vehicle type were common factors. Also, driver's age was important in female drivers cluster; the geometry of the place and seat belt/helmet usage were important in urban roads cluster; and area type, road type, road direction, and vehicle factor were important in rural roads cluster. Also, the combination of the CART algorithm with oversampling and boosting increased the accuracy of the models. CONCLUSIONS: The analysis results revealed motorcycles, lack of using a helmet or seat belt, curvy roads, roads with two-way undivided and one-way movement direction increased the injury and death of drivers. Collision with fixed object, run-off-road, overturning, falling, and defective vehicles increased the severity of accidents. Female drivers older than 44 years old have a higher probability of fatality. Identifying the factors affecting the severity of driver injuries in such accidents in each province could assist in determining engineering countermeasures and training educational programs to mitigate these crash severities.

A new approach in analyzing the accident severity of pedestrian crashes using structural equation modeling.

BACKGROUND: According to official statistics in Iran, there were 17000 fatalities in road traffic crashes in 2018 that 25% of all crash fatalities belong to pedestrians. In most of the researches related to pedestrians' safety, one aspect of the traffic crash (e.g. the injury or crash severity) is almost considered for the investigation. In order to perform a complete study of the crash, accident size can be utilized which involves different aspects of the crash. Accident size is described in terms of the number of fatalities and injured individuals and the number of damaged and involved vehicles in a crash. METHODS: According to the fact that accident size has multiple indicators and it is not measured directly, traditional methodologies cannot be applied. So, in the present study the effective factors on the accident size of pedestrian crashes are investigated through structural equation modeling. For the purpose of this study, 3718 pedestrian-involved crash data occurred in Isfahan province is used for the modeling. The independent variables are weather conditions, road surface conditions, time, horizontal and vertical alignments, road type and location, driver's gender and age, vehicle type, pedestrian's age, gender and clothing color. RESULTS: The results indicated that highways, the pedestrians' invisibility, female and old-aged pedestrians, heavy vehicles, old-aged and female drivers are related to the increase of the accident size in pedestrian crashes. These results denote that the mentioned variables are associated with the higher number of injuries, fatalities, the higher number of involved and damaged vehicles in a crash. CONCLUSIONS: Present study shows the importance of considering safety improvement measures in highways, educating the people in the society about the traffic safety, the separation of pedestrian and motor vehicle traffic flow and considering the old people in policies and programs for mitigating the accident size.

An investigation of the relationship between demographic variables, driving behaviour and crash involvement risk of bus drivers: a case study from Iran.

The aim of this study was to model bus drivers' crash involvement risk as a function of their demographic factors and driving behaviour. 177 bus drivers completed the bus driver risk index questionnaire. 19.2% of respondents had been involved in at least one at-fault crash during the past 3 years. In addition, age group and having a second job were found to affect the crash involvement rate. Smoker drivers reported significantly lower scores in patient driving and anxious driving factors. Results also indicated that vehicle ownership could improve hazard monitoring and thrill-seeking behaviours of bus drivers. Logistic regression suggested that drivers ≥55 years old are 5.4 times more likely to be involved in crashes, compared with drivers <35 years old. Model results also implied that the odds of crash involvement would decrease by 39% for each one-unit improvement in the scores of hazard monitoring behaviour. Implications are further discussed.

A bivariate random effects spatial model of traffic fatalities and injuries across Provinces of Iran.

From 2005-2015, Iran has experienced a 41.3 % decrease in road fatalities and an 11.1 % increase in non-fatal injuries. However, the trend differs across Iran provinces, and hence identifying factors that relate to road fatality and injury counts is an essential tool for improving road safety management programs and policies in the provinces. In this study, a statistical model was developed within a Bayesian framework with the aim of examining the annual fatal and non-fatal injury counts in the provinces of Iran during the period 2005-2015. Specifically, a bivariate spatial negative binomial Bayesian model with random effects was specified and estimated to account for unobserved heterogeneity due to the simultaneity effect between fatal and non-fatal injuries, the presence of province-specific factors, and the spatial correlation between neighboring provinces. All the three effects were found to significantly relate to the frequency of both injury types. Results also indicated that overall fuel consumption and share of diesel fuel consumed were positively related to fatal and non-fatal injuries. Higher population proportions of under 15, and 15-30 years of age were found to be positively associated with fatalities and negatively with non-fatal injuries. Furthermore, the annual number of hot-spots modified per 100 km of rural roads is associated with a decrease in fatalities. Results also suggest that the number of speed cameras operating on rural roads (within a province) might significantly decrease both fatal and non-fatal injuries. Accordingly, the implementation of active and targeted hot spot programs as well as speed camera programs are likely to improve safety performance of the provinces, and help to prioritize area-wide safety initiatives and programs.

Factors contributing to intercity commercial bus drivers' crash involvement risk.

The aim of this study was to examine the influence of demographic, environmental, and occupational factors as well as behavioral characteristics of intercity bus drivers on their crash involvement risk. A total of 107 intercity bus drivers from Tehran, Iran, participated in the study. Logistic regression model suggested that smokers, those who drive during night to morning, less experienced drivers, and those who operate older buses are more likely to be involved in crashes. In addition, a 1-unit increase in the weekly driving hours might significantly increase the drivers' crash involvement risk. The model results also indicated that hazard monitoring, fatigue proneness, and thrill seeking might be considered other significant predictors of crash involvement risk. Implications of results are discussed.

Which set of factors contribute to increase the likelihood of pedestrian fatality in road crashes?

This study aimed to explore the combination of factors and circumstances that could increase the likelihood of a pedestrian crash to be fatal. Six pedestrian crash clusters identified in our previous study on 34,178 crashes occurred in Iran, were employed in the current work and the association rules technique was used as the analysis tool. Based on the results, jaywalking or waiting beside the road on poorly illuminated locations of those segments of rural roads that pass through residential/agricultural districts substantially increased the fatality risk of pedestrian (Lift = 3.4). Therefore, appropriately illuminated locations need to be designed on these segments of rural roads for pedestrians to wait beside or cross the road safely. In case of motorcycle-pedestrian crashes, inattention to yield sign, especially in residential areas, might significantly increase the fatality risk of pedestrian (by a factor of 8.1). Also, in those crashes where the motorcyclist is under 19 years old (i.e. unlicensed) and the pedestrian is over 60, the crash could be 5.3 times more likely to be fatal. More strict law enforcement over unlicensed motorcyclists is required as they were found to involve in more severe pedestrian crashes. The combined use of clustering analysis and association rules discovery should not be considered as an alternative to other modelling techniques, but as a complementary descriptive method to be used in road safety research.

Modeling the effect of operator and passenger characteristics on the fatality risk of motorcycle crashes.

BACKGROUND: In Iran more than 25% of crash fatalities belong to motorcycle operators and passengers in the recent years, from which about 20% are related to passenger fatalities. METHODS: The aim of this study was to investigate the motorcycle operator and passenger characteristics as well as other contributory factors that may affect the fatality risk of motorcyclists involved in traffic crashes. To this end, motorcycle crash data between 2009 and 2012 was extracted from Iran traffic crash database and a logistic regression analysis was performed to obtain odds ratio estimates for each of the study variables. RESULTS: The fatality risk of motorcyclists has a direct relationship with the number of pillion passengers carried. Results also indicate that the amount of increase in the likelihood of having a fatality in a motorcycles crash is considerably higher when the operator is accompanied by a male passenger of the same age. Furthermore, results showed that if the crash is occurred in the darkness, on curves, in rural areas and on highways, then the crash would be more likely to be fatal. Moreover, the head-on collisions, older operators, unlicensed operators and not using a safety helmet were found to increase the likelihood of a fatality in a motorcycle crash. CONCLUSIONS: Preventative measures such as, imposing stricter rules regarding safety helmet usage and confining the number of pillion passengers to one, might be implemented to reduce the fatality risk in motorcycle crashes. In addition, more appropriate infrastructures for penalizing offending motorcyclists could also reduce the frequency of law violations such as not wearing helmet or riding without motorcycle license, which in turn, would result into a reduction in the fatality risk of motorcycle crashes.

A data mining approach to investigate the factors influencing the crash severity of motorcycle pillion passengers.

INTRODUCTION: Motorcycle passengers comprise a considerable proportion of traffic crash victims. During a 5 year period (2006-2010) in Iran, an average of 3.4 pillion passengers are killed daily due to motorcycle crashes. This study investigated the main factors influencing crash severity of this group of road users. METHOD: The Classification and Regression Trees (CART) method was employed to analyze the injury severity of pillion passengers in Iran over a 4 y ear period (2009-2012). RESULTS: The predictive accuracy of the model built with a total of 16 variables was 74%, which showed a considerable improvement compared to previous studies. The results indicate that area type, land use, and injured part of the body (head, neck, etc.) are the most influential factors affecting the fatality of motorcycle passengers. Results also show that helmet usage could reduce the fatality risk among motorcycle passengers by 28%. PRACTICAL APPLICATIONS: The findings of this study might help develop more targeted countermeasures to reduce the death rate of motorcycle pillion passengers.

Identifying significant predictors of head-on conflicts on two-lane rural roads using inductive loop detectors data.

OBJECTIVE: To identify the significant factors that influence head-on conflicts resulting from dangerous overtaking maneuvers on 2-lane rural roads in Iran. METHODS: A traffic conflict technique was applied to 12 two-lane rural roads in order to investigate the potential situations for accidents to occur and thus to identify the geometric and traffic factors affecting traffic conflicts. Traffic data were collected via the inductive loop detectors installed on these roads, and geometric characteristics were obtained through field observations. Two groups of data were then analyzed independently by Pearson's chi-square test to evaluate their relationship to traffic conflicts. The independent variables were percentage of time spent following (PTSF), percentage of heavy vehicles, directional distribution of traffic (DDT), mean speed, speed standard deviation, section type, road width, longitudinal slope, holiday or workday, and lighting condition. RESULTS: It was indicated that increasing the PTSF, decreasing the percentage of heavy vehicles, increasing the mean speed (up to 75 km/h), increasing DDT in the range of 0 to 60 percent, and decreasing the standard deviation of speed significantly increased the occurrence of traffic conflicts. It was also revealed that traffic conflicts occur more frequently on curve sections and on workdays. The variables road width, slope, and lighting condition were found to have a minor effect on conflict occurrence. CONCLUSION: To reduce the number of head-on conflicts on the aforementioned roads, some remedial measures are suggested, such as not constructing long "No Passing" zones and constructing passing lanes where necessary; keeping road width at the standard value; constructing roads with horizontal curves and a high radius and using appropriate road markings and overtaking-forbidden signs where it is impossible to modify the radius; providing enough light and installing caution signs/devices on the roads; and intensifying police control and supervision on workdays, especially in peak hours.