Clues in pedestrian-vehicle collisions and their significance for reconstruction of accidents

Investigations of clues in 87 fatal pedestrian-car accidents which took place with erect posture of the body are reported. Traces of paint proved to be most important clues transferred from the vehicle to the pedestrian's clothing. They derived from the outer paint layer of the collision sites at the front of the vehicle and occurred in 49% of the cases investigated. As has been shown by light and scanning electron microscopic investigations, there is intensive contact between the textile fibers and the paint traces which can be explained by action of heat in the collision. The higher the collision speed, the more readily paint is rubbed off. Because traces of rubbed off paint mark the site of the vehicle impact and indicate the color of the vehicle, they have a high evidence value for reconstruction of the accident. This also applies to traces of molten plastic material as well as to rubbed off chrome and rubber. In contrast to the prevalent view, paint splitters are unsuitable for determining the impact direction. Textile microtraces, traces of blood, hair and tissue occur as transferred clues from the pedestrian to the vehicle. These clues do not permit any statements with regard to the impact direction. They must be evaluated in connection with the remaining clues and the injuries.     

Fatal pedestrian-bicycle collisions

Although, fatal collisions between pedestrians and bicycles are relatively rare, they are still of forensic relevance because of the need to explore the circumstances of the accident. Based on three reconstructed cases, situation and injury patterns are presented that might prove useful in future cases: usually the person causing the accident is the cyclist while the pedestrian generally suffers more severe injuries; the situation at the site of accident is important for its reconstruction: end location of the persons involved in the accident, injuries and traces on pedestrians and cyclists, traces at the site of accident and on the bicycle; because of the lack of pre-crash traces and any eyewitness accounts, the pedestrian's injuries are the best starting point for the reconstruction of the accident; a characteristic wound on the lower leg of the pedestrian that reveals the initial impact between the front wheel and the leg is crucial not because of its seriousness, but because of its external morphology; the injuries that can be expected by the following impact between body and handlebar are unspecific and only minor; the most severe injuries to the pedestrian as a result of the accident are caused secondarily by falling and hitting the head on the road; the fall of the cyclist, however, corresponds to a throw-off followed by a sliding phase with less impact load when the head hits the ground [maximum abbreviated injury scale 1 (MAIS 1)]; the cyclists involved are mainly younger persons on fashionable bicycles (here: mountain bikes); in the great majority of cases, the injured pedestrians are frail, elderly people with a lower tolerance of trauma.     

Evidential value of injuries useful for reconstruction of the pedestrian-vehicle location at the moment of collision

The paper presents final results of the studies concerning the usefulness of knee, ankle, hip, pelvis and neck injuries in reconstructing the circumstances of car-to-pedestrian accidents. Each type of injuries was evaluated with regard to possible reconstruction of the victim's position (upright or recumbent) at the moment of collision and in the upright hits-the side of the pedestrian's body hit. In each group, a chance of proper reconstruction of the pedestrian's location (which determined the frequency of injury pattern assumed as the typical one of a given position or impact side) and error risk (percentage of cases in which the injury pattern showed improper position or impact side) were calculated. These data were compared with similarly calculated possibilities of deducing based on the classical "bumper" injuries to soft tissues and "bending" fractures of the lower limb bone diaphyses. It was shown that the bone bruises within the knee epiphyses were very specific evidence for upright hits as they confirm the limb load by body mass at the moment of pathological dislocation of joint structures on impact. The evidential value of knee injuries was found to be similar to that of other "classical" methods based on bumper injuries or even higher in lateral and front hits. The injuries to the remaining structures were less frequently found and their correlation with the victim's position or impact side was lower. Nevertheless, once the whole complex of these injuries is taken into consideration the chances of proper reconstruction of the pedestrian-vehicle location increase and the risk of opinion error is minimized.     

Knee joint injuries as a reconstructive factors in car-to-pedestrian accidents.

Knee joint injuries were found in 214 out of 357 fatal pedestrian victims of traffic accidents (60%). The cross-sections of tibial and femoral epiphyses revealed bone bruises (due to compression and avulsion) and the percentage of victims with knee injuries increased to 80% (in the group of lateral impacts - 94%). The bone bruises in the central tibial and femoral condyles were observed only in victims hit in an upright position. There was a strong correlation between the side of impact on the extremities in medium sized pedestrians (from the front, back, lateral and medial side) caused by passenger cars and the mechanism of knee injuries (hyperextension, anterior dislocation of the proximal tibial epiphysis in relation to the femoral condyles, valgus and varus flexion). In the cases of very low impacts (e.g. in very tall victims hit by rapidly breaking wedge-shaped cars) or very high impact (e.g. in very short victims or truck hits) the "reversed" complexes of injuries were found (lever principle). These findings showed that knee joint injuries are useful for determining the car-pedestrian location on collision and the type of vehicle (in hit-and-run accidents).     

A Holistic Multi-Scale Approach to Using 3D Scanning Technology in Accident Reconstruction

Three-dimensional scanning and documentation methods are becoming increasingly employed by law enforcement personnel for crime scene and accident scene recording. Three-dimensional documentation of the victim's body in such cases is also increasingly used as the field of forensic radiology and imaging is expanding rapidly. These scanning technologies enable a more complete and detailed documentation than standard autopsy. This was used to examine a fatal pedestrian-vehicle collision where the pedestrian was killed by a van while crossing the road. Two competing scenarios were considered for the vehicle speed calculation: the pedestrian being projected forward by the impact or the pedestrian being carried on the vehicle's bonnet. In order to assist with this, the impact area of the accident vehicle was scanned using laser surface scanning, the victim was scanned using postmortem CT and micro-CT and the data sets were combined to virtually match features of the vehicle to injuries on the victim. Micro-CT revealed additional injuries not previously detected, lending support to the pedestrian-carry theory.     

Ankle joint injuries as a reconstruction parameter in car-to-pedestrian accidents

The study has assessed the usefulness of ankle joint injuries for deducing about the presumable location of a pedestrian in relation to a motor vehicle at the moment of collision. A statistically significant correlation was found between the direction of impact and the mechanism of ankle joint injuries. Such injuries were found in 113 of 317 pedestrian, fatal victims of road traffic accidents (36%). In the cases of impacts on the medial surface of the lower limb, the injuries associated with the supination mechanism were six times more frequent than the injuries associated with the pronation mechanism, while in the group of impacts on the limbs from the lateral side those connected with the pronation mechanism were four times more frequent. In victims hit from the back, the injuries connected with the plantarflexion mechanism were found almost four times more frequent than the dorsiflexion mechanism and in victims hit from the front in three of the five damaged joints the dorsiflexion component was observed (without any plantarflexion case). Less frequent "pronation injuries" in the limbs hit from the medial side and "supination injuries" in the limbs hit from the lateral side as well as "dorsiflexion injuries" in victims hit from the back predominantly occurred in impacts to the pelvic area, i.e. resulting from collisions with a van or lorry. Injuries of upper ankle joints are, thus, useful for reconstructing the presumable location of the pedestrian in relation to the vehicle at the moment of collision, especially, when the vehicle involved in the accident is known.     

基于固定参数的汽车与行人碰撞计算机模拟实验

目的选定固定参数进行计算机模拟碰撞实验．分析不同车型、碰撞车速以及碰撞接触位置对事故过程及人体损伤情况的影响。方法基于多刚体动力学方法建立汽车（大客车、小客车、小轿车和货车）和人体模型,并按照不同碰撞车速（20、30、40、50和60km／h）和不同碰撞接触位置（行人正前方、侧方和正后方）进行模拟碰撞．分析碰撞运动过程以及生物力学响应情况（头部、颈部及下肢）。结果碰撞车型和碰撞接触位置一致的情况下碰撞过程相似（碰撞车速≤60km／h）．头部加速度、上颈部轴向受力以及下肢轴向受力呈现一定的生物力学响应规律。结论基于多刚体动力学方法的模拟碰撞技术研究可再现事故过程中人体的生物力学响应规律。     

Neck injuries as a reconstructive parameter in car-to-pedestrian accidents

The study has assessed the usefulness of injuries to the ligamentous, muscular and vascular neck structures for deducing about the presumable location of a pedestrian in relation to a motor vehicle at the moment of collision. The localisation of haemorrhagic suffusions in the lower insertions of the scalene (mainly) and sternocleidomastoid muscles has shown a correlation with the direction of the inertia force. No correlation has been observed between the direction of impact and damages to the cervical vascular bundles and the localisation of haemorrhagic suffusions in the upper insertions of the nape muscles. In some cases, injuries to the ligaments of the cervical vertebrae made up the complex characteristic of the direction of acting forces. The injuries of soft tissues and ligaments can, thus, facilitate the deductions about the direction of impact. However, the type of a car involved in the accident and the possibility that these injuries resulted from direct head or neck trauma should be considered.     

轿车冲撞行人的力学模型分析

目的通过建立"力学模型",分析轿车冲撞行人的力学过程,进而讨论使行人发生倒立时冲撞轿车的行驶车速的临界值。方法把人体简化成杆状刚体,运用动量定理、动量矩定理和动能定理,分析冲撞过程和有关数值计算。结果理论计算估计数值和轿车冲撞假人实验结果相吻合。结论本文提供了一种有效估算方法,针对具体情况要选择适当参数进行计算,也可在此基础上进行修正。     

Severity of vehicle bumper location in vehicle-to-pedestrian impact accidents

Pedestrian protection is one of the key topics for safety measures in traffic accidents all over the world. To analyze the relation between the collision site of the vehicle bumper and the severity of the lower extremity injuries, we performed biomechanical experiments. We compared the applied external force and the risks of subsequent injuries between the impact of the center and side positions of the front bumper. These comparisons were performed by practical impact tests with eight typical different types of cars which were typical of the current vehicle fleets. The tests were made using the TRL legform impactor which was a mechanical substitute of a pedestrian lower extremity. The TRL impactor is used all over the world for assessing the safety of car bumpers. It was found that the risks of lower extremity injuries in the impacts at the side positions, in front of the vehicle's side member, were significantly higher than those at the center. In the tests, we found that foam materials around the rigid front cross member had a significant effect on reducing the lower extremity injury risks and especially tibia fracture risk against vehicle bumper center collisions, but had little effect at the sides of the bumper over the vehicle's side members where the foam was thinner. We also found that the front shape of the vehicle affected the risk of ligaments injuries. According to these results, the information of impact locations of cars in vehicle-to-pedestrian traffic accidents is valuable for clinicians to diagnose patients with lower extremity injuries in traffic accidents and for forensic pathologists to analyze the accident reconstruction. Furthermore, the results suggest that testing of the bumper area in front of the main longitudinal beams should be included in the car safety legislation to require pedestrian safety.     

Was the pedestrian hit in an erect position before being run over?

If a pedestrian was run over by a car, the question can arise whether there was a preceding collision while the pedestrian was in an erect position. From a total of 53 selected autopsy reports, the findings associated with accidents known to involve running over in isolation (n=32) were compared to findings associated with a combined mechanism of a primary impact in an erect position and subsequent running over (n=21). Findings exclusively present in the combined group were wedge-shaped bone fractures ("Messerer"-wedges, 38%), glass fragment injuries (24%), traumatic amputations (10%), traces of car paint on the lower extremities (50%) and abrasions of the shoe soles (17%). These findings can be considered specific for a primary impact in an erect position. Fractures of the cervical and lumbar spine were present in the combined group in 33 and 17%, respectively. In contrast, in the run over group, there was only one case of fracture of the cervical and one of the lumbar spine and both cases involved direct contact with a car wheel. Fractures of the cervical and lumbar spine are, therefore, very indicative for a primary impact. "Bumper injuries", sacroiliac dislocations and fractures of the thoracic spine were approximately 2.5 times more common in the combined group than in the run over group. In the vast majority of cases, a clear differentiation between the two groups is, therefore, possible on the basis of the autopsy findings. This is especially relevant if an inspection of the car cannot be performed after a hit-and-run accident, which occurred in 26% of the cases in this study. In addition, the blood alcohol levels were higher in the run over group (mean=2.14g/l) as compared to the combined group (mean=1.53g/l).     

试论非法取得证据的可采性

刑事诉讼程序的双重价值对非法取得证据的证据能力具有重要影响，明确此点，将有助于我国相关法律制度的发展和完善。     

Interviewing women bereaved by homicide: assessing the impact of trauma-focused research

Abstract

The use of swearwords has hardly been investigated scientifically. Virtually nothing is known about the efficacy of swearing. The present studies set out to investigate whether the inclusion of swearwords in a testimony increases the believability of that statement. In study 1, respondents were simply asked whether they believed that using swearwords is a sign of credibility, a sign of deceit, or neither. In the second and third study, participants had to read fictitious testimonies of a suspect and a victim, respectively. Participants were exposed to testimonies with or without swearwords. The results suggested that people self-reported to find swearwords a sign of deceit (study 1), but when actually confronted with a statement, the opposite turned out to be the case (studies 2 and 3). That is, testimonies containing swearwords were perceived as more credible than swearword-free testimonies. Hence it is concluded that swearing increases believability of statements.     

The forensic investigation of vehicle–pedestrian collisions: A review

Rapid urbanisation, a steady increase in the number of vehicles, speeding, negligence in road safety, and other factors have led to the inevitable worldwide growth of road traffic accidents involving pedestrians. According to the ‘Global Status Report on Road Safety’ released by the World Health Organization, road traffic collisions are one of the leading causes of death for people of all ages, with approximately 1.35 million road fatality deaths occurring globally each year. Figures from the report also highlight that a large part of road deaths involves pedestrians as the most vulnerable road users. Therefore, forensic examination of vehicle–pedestrian collisions has become increasingly important in the detection, investigation and reduction of road casualties and permanent development of this discipline is urgently needed. Thus, this article aims to review the capability and effectiveness of forensic examination in tackling road fatalities and explores the most important aspects of this discipline, such as nature of a vehicle–pedestrian collision, common issues resolved by this type of examination and typical physical evidence used in the reconstruction of vehicle–pedestrian collisions. Moreover, the paper outlines the latest advances and approaches in the field.     

Two Simple Formulas for Evaluating the Lower Bound of the Impact Velocity in Vehicle–pedestrian Accidents

Formulas for evaluating the lower bound of the impact velocity are valuable in vehicle–pedestrian accident reconstruction. The theory of classical mechanics and four hypotheses were employed to derive formulas; the research results and simulation/accident tests were employed to validate their feasibility. Then, two simple formulas were developed according to the distance between the rest positions of the vehicle and the pedestrian and the flight‐phase distance. The results showed that the evaluated results by the two proposed formulas are inferior to the existing results. The influence of a roadside step on the impact velocity, which decreased with an increase in the flight‐phase distance and a reduction in the road slope, was evaluated. Based on a real accident, the study concludes that the lower bound can be easily obtained with the proposed formulas, which can be used to determine the evaluated impact velocity during simulations.     

Dragging deaths: a case in point

A 16-year-old boy was riding his bicycle when he was struck by a truck. He was dragged over 2 1/2 miles (4 km) before he was deposited on the side of the road. The injuries evident at autopsy revealed the boy died from dragging and not from the initial impact. The scene, and the autopsy findings, will be discussed.     

90例行人撞击伤案例分析

目的 探讨行人交通事故和致伤车辆类型的关系,总结其规律.方法 回顾90例行人交通事故案例,分析致伤车辆、损伤部位、损伤特点、严重程度之间的关系. 结果 不同类型致伤车辆所致的撞击伤好发部位取决于受撞击时人体的姿势和车头突出部位的高度,其损伤特点与作用力大小、方向和接触面光滑程度相关. 结论 通过对行人撞击伤的损伤部位、损伤特点、严重程度的分析,可以推断致伤车辆类型.     

Identification process in mass graves from the Spanish Civil War II

The identification process of a mass grave from the Spanish Civil War (1936-1939) is presented. The presumed location of the grave, as well as the presumed number and identities of the persons buried in the grave were obtained exclusively from witnesses' and relatives' testimonies. In agreement with the testimonies, the grave was located at the indicated location and five skeletons were exhumed. Also in agreement with the testimonies, the osteological and DNA study led investigators to propose the identification of two kin groups, a father and his son and a pair of brothers. But the genetic study did not support the identification of a fifth man presumed to have been buried in the grave. The differences and similarities between this case and another case reported earlier are discussed.