Vehicle-pedestrian Accidents Research Articles

Modeling and Analysis Method of Vehicle-pedestrian Crash Accidents Based on Contact Characters

Injury of pedestrian and deformation of vehicle are the important information in the accidents.In the simulation analysis for vehicle-pedestrian crash accident,usually it uses vehicle model by rigid ellipsoid and the numerical dummy with the standardizing body.The shape error causes large different on the simulation results,and there is large penetrate in the contact position between vehicle and pedestrian when the speed is high.Based on the scaling technology,the method for estimating the anthropometry parameters of the six main parts of the given victim is studied.On the other hand,the true shape vehicle model based on shell element is adopted.The contact position between vehicle and pedestrian uses plastic materials and the equivalent stiffness curve of material is established to simulate the real contact and vehicle deformation.Through the equivalent contact model establishment between vehicle and pedestrian,it can improve simulation accuracy,and realize the balance between the calculation accuracy and the computational efficiency.The simulation results show that the accident reconstruction results can obtain with high accuracy,reliability.And it can meet accident reconstruction requirement under different vehicle speed and collision deformation.The study provides a new solution for vehicle large deformation.

Situational Factors of Influencing Drivers to Give Precedence to Jaywalking Pedestrians at Signalized Crosswalk

A large number of fatalities are caused by the vehicle-pedestrian accidents. Under a potential conflict between the vehicle and jaywalking pedestrian, giving precedence to the pedestrian will be a proper decision taken by the driver to avoid collision. Field traffic data has been collected by video recording and image processing at two signalized crosswalks. Vehicle speed performance in the single vehicle-pedestrian encounter and platoon vehicle-pedestrian encounter were analyzed for understanding the driver behavior in the conflict process. Binary logit model was proposed to estimate the drivers' giving precedence influenced by the situational factors and the model was validated to predict the drivers' choices accurately. The vehicle speed, pedestrian speed, pedestrian lateral distance and the vehicle longitudinal distance to the conflict point were proved to affect the drivers' choices in platoon driving. The research results would hopefully be helpful to the design of intelligent vehicles and pedestria...

Research on the biomechanics friction characteristics based on the typical bus–pedestrian accident

The simulation precision of the vehicle–pedestrian accident is influenced by the numerous pre-impact parameters. Among them, the biomechanics friction characteristics of pedestrian exert direct influence on the reconstruction of vehicle–pedestrian accident. Given the complicacy of human body and the traffic accident, it is difficult to chase down the pedestrian–vehicle and pedestrian–road contact characteristics in the accident merely through experiments. The analysis on biomechanics friction characteristics in vehicle–pedestrian accident based on the design of experiment method are discussed in this article. The reliability of the friction characteristics can be verified by the optimization method. Finally, the method is applied to reconstruct a real typical case of a bus–pedestrian accident. The numerical reconstruction results gained by the method have high accuracy and credibility. The study also provides a new way to analyse the vehicle–pedestrian accident cause.

Acquisition and Analysis on 3D Deformation of Windshield Glass in Vehicle-Pedestrian Accident

A method based on the 3D laser scanning is proposed for obtaining and analyzing the windshield's deformation in vehicle-pedestrian accident. With an actual traffic accident of vehicle-pedestrian collision taken for example, point cloud data of windshield’s deformation is scanned by EXAScan 3D laser scanner and the deformed 3D NURBS surface is obtained after fitting process. Based on the discussion about characteristics of curved surface of the vehicle’s front windshield and the principle of continuous curvature, this paper conducts a surface fitting with cubic non-uniform spline according to geometric information of grid surface around the deformation zone, and obtains the pre-deformed surface of windshield by sampling with spline curve. Compared with the pre-deformed surface of vehicle’s windshield, the maximum deformation depth is 48.509mm and its area is 0.3816m2on the right side, while the maximum deformation depth is 36.341mm and its area is 0.2529m2on the left side. The application results in actual traffic accident show that this method can be used to obtain 3D deformation information of overall impact area, which provide a new method for accurately inspecting the windshield’s deformation in vehicle-pedestrian accident. This method also provides a new research idea for quantitative saving the evidence in permanent, and it also has a great value in accident analysis and reconstruction.

Computer simulation of real-world vehicle–pedestrian impacts

This paper describes a study carried out to develop and apply computer analysis tools to simulate real-world accidents between vehicles and pedestrians. The main focus has been the incorporation of realistic pedestrian pre-impact gait motion and to investigate the outcome of real-world impacts. A combination of multi-body, FACET and finite element based vehicle models in conjunction with validated human body models developed by MADYMO were used to simulate and analyse vehicle–pedestrian accident scenarios. European regulations and consumer tests for passenger cars now address vehicle front aggressiveness, and vehicle manufactures have effectively developed design solutions for meeting these requirements. Vehicle frontal geometry and pedestrian pre-impact characteristics play a major role in determining the post-impact kinematics and severity of injury sustained during pedestrian–vehicle contact stage. A unique aspect of this study has been the application of the Injury Severity Index method developed for automotive occupant injury assessment to pedestrians. The injury results from the simulations were measured and the severity assessed by applying a quantitative rating method.

The first collision point position identification method in vehicle–pedestrian impact accident

Vehicle–pedestrian accidents share high frequency of occurrence in fatal traffic accidents in China. According to the Chinese Traffic Safety Regulations, the first collision point is the key factor for responsibility cognisance in related traffic accidents. Usually, the police or other accident investigators determine the first collision point position between vehicle and pedestrian only through experience. The position error of the collision point will lead to inaccurate accident analysis and responsibility judgement. This paper applies computer-simulated reconstruction in vehicle–pedestrian accident investigation and uses optimisation methods to analyse the simulation result. The first collision point position coordinates are set as variables of the optimisation objective function. Through optimisation analysis, first collision point position coordinates can be obtained. And, the reliability of simulation result can be evaluated through the reliability analysis. By reconstructing a real-world vehicle–pedestrian impact accident, the performance of the method is evaluated.

The application for skull injury in vehicle–pedestrian accident

Vehicle–pedestrian impact is one of the major traffic accident types all over the world. In these accidents, head injury is the main factor that causes the pedestrian death. However, numerical human models that have been developed cannot be applied effectively in these accidents either because the head structure is not precise enough to show the local damage or because the model is too complex to ensure the computation efficiency. For instance, the Head Injury Criterion (HIC) of the TNO Hybrid III dummy model could be used for the prediction of skull fracture, and the contact point between the head and the vehicle could give an indication of where the injury occurred. However, the dummy model is not able to show the local stress and damage of the head that is shown in accident autopsy reports. Therefore, the anthropometry-based finite-element head and multibody knockdown pedestrian models have been developed. The knockdown human model cannot only simulate precisely the head damage and more accurate damage position but also improve the computing efficiency. Additionally, the parameter customisation technology is applied for the pedestrian model in order to get rid of using the standard pedestrian model in all cases. The purpose of this paper is to prove the validity for the new pedestrian model applied in accident simulation and optimisation. By reconstructing real-world vehicle–pedestrian impact accidents, the performance of the modelling method is evaluated. The results show that the method is very effective in finding an optimum solution and receiving enough exact head injury value.

Characterization of pedestrian accidents and an examination of infrastructure measures to improve pedestrian safety in Israel

The high share of pedestrian fatalities in Israel provided the impetus for this study which looked for infrastructure solutions to improve pedestrian safety. First, a detailed analysis of pedestrian accidents in 2006–2007, with an emphasis on the infrastructure characteristics involved, was performed; it found that 75% of the fatalities and 95% of the injuries occurred in urban areas, the majority of cases occurring on road sections (not at junctions). About 80% of the accidents took place when a pedestrian crossed the road, the majority of them at non-crosswalk locations or at non-signalized crosswalks. International comparisons showed that the characteristics of fatal pedestrian accidents in Israel were similar to the average pedestrian accident in Europe in terms of accident location, time, and the demographic characteristics of the victims. A typology of pedestrian fatalities in Israel was built for the years 2003–2006; it demonstrated a high share of accidents at these locations: in Jewish or mixed-population towns—not at pedestrian crossings on urban street sections, and both at pedestrian crossings and not at pedestrian crossings at urban junctions; in Arab towns; and on dual-carriageway rural roads. Second, based on a literature study, a summary of about 60 pedestrian-safety-related measures was developed. Third, to diagnose the infrastructure characteristics and deficiencies associated with pedestrian accidents, detailed field studies were carried out at 95 urban locations. A major finding revealed that more than 80% of the sites with a high concentration of pedestrian–vehicle accidents in Israel were situated on arterial multi-lane streets belonging to city centers, where on a micro-level there were no indications of major deficiencies in the basic design elements of most sites. Finally, cross-checking of the safety problems identified and the infrastructure solutions available provided lists of measures recommended for application at various types of sites. It was concluded that in order to generate a significant change in the state of pedestrian injury in Israel, a move from spot treatment to a systemic treatment of the problem is required. A systemic inquiry and the transformation of the urban road network should be performed in order to diminish the areas of vehicle–pedestrian conflicts and to significantly reduce vehicle speeds in areas of pedestrian presence and activity.

Analysis and application of relationship between post-braking-distance and throw distance in vehicle–pedestrian accident reconstruction

Through theoretical analysis and introduction of some empirical parameters, the relationship between post-braking-distance and throw distance was studied concentratedly. Here, the post-braking-distance is the distance a vehicle will travel from the impact position to when it comes to a complete stop. Two useful formulas which are meaningful in vehicle-pedestrian accident reconstruction were finally obtained. The first one can be used to calculate impact speed according to throw distance, while the other one can describe the relationship between post-braking-distance and throw distance. Their feasibility has been validated by comparing with other scholars' empirical formulas and simulation results of software Pc-Crash, respectively. The relationship between post-braking-distance and throw distance has very bright application perspective in vehicle-pedestrian accident reconstruction such as helping policemen obtain more useful evidences, validating credibility of the throw distance, judging whether the vehicle is fully braked or not, determining the impact position etc. Finally its application was demonstrated by three cases, in which the impact speed was also calculated. All results until now have shown that conclusions obtained in this article are feasible and helpful in vehicle-pedestrian accident reconstruction.

GIS Potential in Management of Pedestrian Accidents in Developing Countries

The main objective of this work was to investigate the potential of utilizing geographic information systems (GISs) in identifying hazardous pedestrian accident-prone locations. The study was performed for roads in Irbid city-Jordan for the years 2002 and 2003. Pedestrian accident data was analyzed by pedestrian characteristics, driver characteristics, accident time and location, environmental conditions, vehicle speed and characteristics, and accident severity. Pedestrian accidents were correlated to operational factors, including traffic volume, vehicle speed, pedestrian volume, street length, and access points. Hazardous locations of vehicle-pedestrian accidents were identified using a GIS query builder. Results showed that there was a high potential for GISs in studying pedestrian accidents.

A New Vehicle Speed Estimation Method Based on the Longest Radial Crack on Windshield

Pedestrian-vehicle accident without road marks has long been a headache to accident investigators. This paper suggested a new method with the application of fracture mechanics to estimate impact speed in pedestrian-vehicle. Firstly, a windshield crack propagation model based on the crack initiation model put forward by Freund [1] is established. In the model, crack bluntness coefficient is an unknown parameter, depending on various factors, so speed domain is then divided into five intervals and sample real-world accident cases are employed to the calibrate crack bluntness coefficient in different speed intervals. Further, fourth-order Runge Kutta’s method is used to solve the differential equation. Five additional real-world accident cases are then employed to verify the accuracy of the model. Results show good agreement between the model results and the real impact speeds. Finally, the advantages and limitations of this method are discussed.

Investigation of 184 passenger car–pedestrian accidents

In China, pedestrians were the most common and the most vulnerable of road users, meaning pedestrians were involved in vehicle-pedestrian accidents more frequently. Little attention has been paid to the investigation of such accidents. One surveying group was built to randomly collect vehicle-pedestrian accidents and analyse these accidents from the vehicle–pedestrian crash characteristics and the relationships between the pedestrian injury outcome and the impact speed. 184 pedestrians were injured and killed in these investigated passenger-car-pedestrian accidents. Among the 184 pedestrians involved in these accidents, 151 were crossing road arbitrarily (82.1%). There were only 17 accidents where the pavement and guardrail satisfied the safety standard. The males were the majority of the casualties (64.7%). Pedestrian injury localisations in head, extremities, chest and torso accounted for 68.5%, 68.5%, 24.5% and 15.8%, respectively. Of the fatalities, 71.4% resulted from brain injury. The injury outcome in elderly pedestrians was more severe and the head severe injury proportion in children was more than that of an adult. Multiple injuries were common in pedestrians. The pedestrian injury outcome was relative to the impact speed, i.e. faster the impact speed, higher was the pedestrian's Injury Severity Score (ISS). There were no fatalities under the impact speed of 30 km/h and there were 4.4% of fatalities at the impact speed of 30∼39 km/h. When the impact speed was above 80 km/h, the pedestrians were severely injured or even killed.

No Accident: Traffic and Pedestrians in the Modern City

This paper considers the rise of traffic accidents in the creation of the modern city. The notion of accidents is deconstructed. There is a brief review of current literature on mobilities and then evidence is presented of the shifting configuration of vehicle–pedestrian accidents. The epidemic of traffic accidents of cities in developing world is noted and explained. The incidence of pedestrian traffic accidents is shown to reflect socio‐economic characteristics such as age, class and status. A review of the literature provides evidence of the ways to ameliorate pedestrian injuries. Walksheds are suggested as a focus of concern. The creation of a more pedestrian‐friendly city is proposed.

Reconstruction and Analysis of the Vehicle-Pedestrian Crash Accidents Based on Human Injury Characters

The characters of the two kinds of pedestrian models are studied.The calculation time can be reduced by the multi-body (MB) method,and fine analysis should be finished by finite element (FE) method.In the study,the coupled FE-MB human modeling is considered as the approach for improving the efficiency and accuracy of pedestrian accident reconstruction.For the large proportion of the injury of the lower limb in the vehicle-pedestrian accidents,the FE-MB lower limb model is built and validated by comparing the simulation with the tests.Then,the coupled FE-MB model is applied in a real-world traffic accident case,the velocity of the vehicle can be solved by the MB model according to the contact position between the pedestrian and the auto-body.And the FE lower limb is used to predict the fracture of long bones.The simulation result is consistent to the inspection conclusion of the forensic experts,so it is proved to be correct.With the coupled FE-MB method,the vehicle-pedestrian crash accident can be simulated and analyzed,thus providing a scientific foundation for accident judgments.

Model of Vehicle Velocity Calculation in Vehicle-pedestrian Accident Based on Deflection of Windshield

A vehicle velocity calculation model of vehicle-pedestrian accident is established based on the impact dynamics of rectangular thin plate, according to the deflection of the windshield plate. Proper material parameters are given to windshield and pedestrian head respectively according to the specific situation of vehicle-pedestrian accident. Support type of windshield on the frame is considered as simplified support without affecting the accuracy of the model. During modeling, expression of impact force between head and windshield is suggested in the light of Hertz elastic contact theory and energy conservation law. In addition, the expression of windshield deflection is rewritten based on Navier theory and the relationship between impact velocity and windshield is abtained. Considering the quantitative relations between the impact velocity and vehicle velocity, a calculation model is finally put forward. Comparison with cases of actual vehicle-pedestrian accidents proves the accuracy and reliability of the model. Therefore, this model provides the accident investigators and researchers with a new method to reconstruct the vehicle velocity.

Automatic Optimization Method for Vehicle-pedestrian Collision Accident Reconstruction

To improve the efficiency and objectivity of accident judgments,an automatic optimization method of vehicle-pedestrian accident reconstruction based on numerical simulation is proposed. In this method,the accident process is reconstructed based on full scale dummy multi-body simulation,and its initial conditions are automatically adjusted to optimum solution which can generate the best match between simulation and real accident data. For several types of pedestrian accident,the corresponding optimization model is presented in which the impact speed and/or the braking delay are regarded as the design variables and the displacement of vehicle and pedestrian is used to construct the objective function with the constraints of pedestrian injuries. Because sequential linear programming is used as the optimization algorithm and the optimization is based on rest position as well as pedestrian injury,the above mentioned method is suitable for the nonlinearity of pedestrian accident reconstruction. Using the commercial software,the method is applied to a real-world pedestrian accident in order to prove its feasibility. The simulation is compared with the autopsy report in terms of several pedestrian injuries. Also,the global response surface of the objective function constructed by a full factorial experimental design is used in the evaluation.

Mortality pattern according to autopsy findings among traffic accident victims in Yazd, Iran

To describe mortality pattern and to determine undiagnosed fatal injuries according to autopsy findings among road traffic accident victims in Yazd, Iran. In this retrospective study, 251 victims of road traffic accidents who were admitted to a tertiary trauma hospital over a two-year period (2006 and 2007) and received medical cares were included. Hospital records were reviewed to gather demographic characteristics, road user type, and medical data. Autopsy records were also reviewed to determine actual causes of death and possible undiagnosed injuries occurred in the initial assessment of the emergency unit or during hospitalization. There were 202 males (80.5%) and 49 females (19.5%). The mean (+/-SD) age of fatalities was 34.1 (+/-21.5) years. Pedestrian-vehicle accidents were the most common cause of trauma (100 cases, 39.8%). The most common cause of death was central nervous system injury (146 cases, 58.1%). The other causes were skull base fractures (10%), internal bleeding (8%), lower limb hemorrhage (8%), skull vault fractures (4%), cervical spinal cord injury (3.6%), airway compromise (3.2%), and multifactor cases (5.1%), respectively. Thirty-six fatal injuries in 30 victims (12%) mainly contributed to death according to autopsy, but were not diagnosed in initial assessments. The head (72.2%) and cervical spine (13.8%) regions were the two most common sites for undiagnosed injuries. Training courses for emergency unit medical staff with regard to interpreting radiological findings of head and neck and high clinical suspicion for cervical spine injuries are essential to improve the quality of early hospital care and reduce the mortality and morbidity of traffic accident patients.

Reconstruction model of vehicle impact speed in pedestrian–vehicle accident

Reconstruction of pedestrian–vehicle accident is a worldwide problem. Numerous previous studies have been carried out on accidents with vehicular skid marks or definite pedestrian throw distances. However, little could be done if marks or throw distances cannot be obtained in accident reconstruction. This paper first describes the physical model of dynamic process of pedestrian head impact on windshield glazing. Some simplifications are made to obtain a better and more practical model, including discussing the support boundary conditions. Firstly, the paper modeled the relations between pedestrian impact speed and deflection of windshield glazing based on the impact dynamics and thin plate theory. Later, the relations of vehicle impact speed and deflection are discussed. Therefore, a model of vehicle impact speed versus deflection of windshield glazing is developed. The model is then verified by ten real-world accident cases to demonstrate its accuracy and reliability. This model provides investigators a new method to reconstruct pedestrian–vehicle accidents.

Analysis of Traffic Accident Reconstruction Uncertainty

AbstractThere are many uncertain factors in road traffic accident. It is necessary to consider the uncertainty influence of these factors by random theory to improve the analysis veracity. In order to improve the precision and reliability of traffic accident analysis and reconstruction, random theory and the probabilistic perturbation method were introduced in this work for the uncertainty analysis of traffic accident because of the existing of uncertainty factors universally. The confidence interval and confidence of parameters were obtained expediently by the uncertainty analysis, and the precision of traffic accident analysis or reconstruction was improved. A typical vehicle-pedestrian accident was investigated by the method proposed, and the calculated result is contrasted with Monte Carlo simulation method, which proves that the method adopted in the paper is accurate and effective.

Observational Failures/Distraction and Disease Attack/Incapacity as Cause(s) of Fatal Road Crashes in Finland

Objective: To study the incidence of health-related conditions and observational failures/distraction (OFD) as an immediate cause for fatal motor vehicle accidents (FMVA) and to correlate them with driver's age. Methods: Retrospective study of all FMVA in Finland secondary to OFD from January 1995 to December 2005 and FMVA secondary to a disease attack/incapacity (DA) from January 2003 to December 2004. The data were based on the final investigation reports of the Finnish Motor Insurers' Centre. The cases were categorized into the three following groups: 1) vehicle crashes due to OFD of the driver, 2) pedestrian-vehicle accidents due to the driver's OFD, and 3) pedestrian-vehicle accidents due to the pedestrian's OFD. In the second part, 54 autopsy reports from FMVA resulting from a DA of the driver between the years 2003–2004 were revisited and the health-related causes of the accident were investigated. Results: Oldest age group (> 65 years) had the highest prevalence of FMVA secondary to an OFD. We estimated that in 20–30% of all FMVA affecting subjects > 65 years an impairment of cognitive functions might have played a role. Analysis of the DA that the inspection teams had concluded to have been the immediate risk factor for the FMVA revealed that these accidents accounted for 10.3% of all FMVA in 2003–2004. Cardiovascular diseases were most often involved. Conclusions: OFD as an immediate cause of FMVA began to play a role from the age of 60 years onwards. The role of health conditions as a cause of FMVA was higher than expected. Cardiovascular disease (70%) was found to be the leading medical condition that inhibited the driving task among the DA related to FMVA in Finland.