Situations of car-to-pedestrian contact

OBJECTIVE

To reduce the severity of injuries and the number of pedestrian deaths in traffic accidents, active safety devices providing pedestrian detection are considered effective countermeasures. The features of car-to-pedestrian collisions need to be known in detail to develop such safety devices.

METHODS

Because information on real-world accidents is limited, this study investigated near-miss situations captured by drive recorders installed in passenger cars. We showed similarities of the contact situation between near-miss incidents and real-world fatal pedestrian accidents in Japan. We analyzed the near-miss incident data via video capturing pedestrians crossing the road in front of forward-moving cars. Using a video frame captured by a drive recorder, the time to collision (TTC) was calculated from the car velocity and the distance between the car and pedestrian at the moment that the pedestrian initially appeared.

RESULTS

The average TTC in the cases where pedestrians were not using a pedestrian crossing was shorter than that in the cases where pedestrians were using a pedestrian crossing. The average TTC in the cases where pedestrians emerged from behind obstructions was shorter than that in the cases where drivers had unobstructed views of the pedestrians.

CONCLUSIONS

We propose that the specifications of the safety device for pedestrian detection and automatic braking should reflect the severe approach situation for a pedestrian and car including the TTC observed for near-miss incidents.

Features of pedestrian behavior in car-to-pedestrian contact situations in near-miss incidents in Japan

OBJECTIVE

The objective of this study is to evaluate the severe conditions between car-to-pedestrian near-miss situations using pedestrian time-to-vehicle (pedestrian TTV) which is the time when the pedestrian would reach the forward moving car line.

METHODS

Since the information available from the real-world accidents was limited, the authors focused on the near-miss situations captured by driving recorders installed in passenger cars. In their previous study, the authors found there were some similarities between accidents and near-miss incidents. It was made clear that the situations in pedestrians' accidents could be estimated from the near-miss incident data which included motion pictures capturing pedestrian behaviors. In their previous study, the vehicle time-to-collision (vehicle TTC) was investigated from the near-miss incident data. The authors analyzed data for 101 near-miss car-to-pedestrian incident events in which pedestrians were crossing the roads in front of a forward-moving car at an intersection or on a straight road. Using a video of near-miss car-to-pedestrian incidents captured by drive recorders and collected by the Society of Automotive Engineers of Japan (J-SAE) from 2005 to 2009, the pedestrian TTV was calculated. Based on the calculated pedestrian TTV, one of the severe conditions between car-to-pedestrian near-miss situations was evaluated for pedestrians who emerged from behind an obstruction such as a building, a parked vehicle and a moving vehicle.

RESULTS

Focusing on the cases of the pedestrians who emerged from behind an obstruction, the averages of the vehicle TTC and pedestrian TTV were 1.31 and 1.05 seconds, respectively, and did not demonstrate a significant difference. Since the averages of the vehicle TTC and pedestrian TTV were similar, there would be a higher possibility of the contact between a car and pedestrian if the driver and pedestrian were not paying any attention.

CONCLUSIONS

The authors propose that a moving speed of a pedestrian surrogate "dummy" should be determined considering the near-miss incident situations for the evaluation of a CDMBS for pedestrian detection. The authors also propose that the time-to-collision of the dummy to the tested car during the evaluation of the performance of the CDMBS for pedestrian detection should be determined considering the time such as the vehicle TTC in this study. Additionally or alternatively, the pedestrian TTV should be considered, in which the worst situation was assumed for a car that was moving toward a pedestrian without braking due to the car driver's inattentiveness and the pedestrian not slowing down their walking speed or stopping.

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.

Sudden illness while driving a vehicle--a retrospective analysis of commercial drivers in Japan

OBJECTIVE

We performed a retrospective analysis of commercial drivers to clarify the background of incidents of sudden illness while driving.

METHODS

The analysis used reports submitted by employers to the Japan Ministry of Land, Infrastructure, Transport, and Tourism regarding commercial drivers who had been ordered to stop driving owing to health problems.

RESULTS

Of 211 cases with an average work history of 15.2 years, there were 88 bus drivers, 70 taxi drivers, and 53 truck drivers, 36.0% of who had died as a result of their disease. Among taxi and truck drivers, more than 70% of incidents were due to cardiac, aortic, and cerebrovascular disease. More than 80% of these were unable to avoid traffic accidents caused by sudden illness. However, among bus drivers, cardiac, aortic, and cerebrovascular disease accounted for only 23.5% of incidents, and accidents were avoided in more than half of the cases. The duration between starting work and the incident time was significantly shorter among bus drivers [mean 3.3 hours, standard deviation (SD) 3.1] than taxi (7.7 hours, SD 5.8) and truck (7.2 hours, SD 6.3) drivers (P<0.01).

CONCLUSIONS

The difference between the sudden illness rates of taxi and truck drivers and those of bus drivers is due to both reporting bias and differences in the awareness needed to prevent disabling events while driving. As a precaution, physicians should advise commercial drivers to stop driving as soon as they detect slight discomfort. To prevent accidents, more assertive health promotion aimed at professional drivers is needed.

Support for stroke patients in resumption of driving: patient survey and driving simulator trial

BACKGROUND

Encouragement of stroke patients to resume driving is important to promote their reintegration into the community. Limited rehabilitation has been performed in this regard, owing to lack of specific knowledge on the part of medical staff. To establish an effective support program for stroke patients who wish to resume driving, we propose comprehensive training by medical staff using a driving simulator.

METHODS

A survey of stroke patients admitted to the Tokyo Metropolitan Rehabilitation Hospital was first performed. A questionnaire was sent to 525 patients. Of 218 responses, the answers of 118 patients who had been driving before their stroke were analyzed. More than 80% of stroke patients did not obtain enough information about resuming driving during their hospital stay, and 38.1% of patients would have liked to have had driving training with a simulator. From these results, we set out to determine the effect of driving training using a realistic and technically advanced driving simulator. Twenty-four stroke patients and 20 healthy controls were included in the study.

RESULTS

Repeat training with the simulator resulted in an increased ability to perform braking and an improvement in driving ability. The majority of stroke patients who had the mental and physical ability to drive a car were likely to be assessed as being able to resume driving as a result of the training program.

CONCLUSION

This study indicates that comprehensive support by medical staff and provision of adequate information about resumption of driving and the opportunity for training on a driving simulator are likely to aid resumption of driving by stroke patients, thus enhancing their rehabilitation and social reintegration.

Differential gene expression of multiple chondroitin sulfate modification enzymes among neural stem cells, neurons and astrocytes

Chondroitin sulfate/dermatan sulfate (CS/DS) polysaccharides have been reported to play a crucial role in the proliferation and maintenance of neural stem cells (NSCs). However, little is known about the structural changes and functional role of CS/DS chains in the differentiation of NSCs. Western blots of NSCs, neurons and astrocytes in culture, with three CS-polysaccharide antibodies of different specificities, revealed marked differences in CS structure among the three cell types. To confirm this finding, we measured gene expression levels of CS sulfotransferases and C5-epimerase in these cell types, as these are responsible for producing the high structural diversity of CS/DS. Expressions of chondroitin 4-O-sulfotransferase, chondroitin 6-O-sulfotransferase, and N-acetylgalactosamine 4-sulfate 6-O-sulfotransferase mRNAs were low in cultures of differentiated neural cells, such as neurons and astrocytes, in comparison to NSCs. In contrast, expressions of uronyl 2-O-sulfotransferase and C5-epimerase mRNAs were higher in the differentiated neural cells than NSCs. Thus, we first provide evidence to support the hypothesis that CS/DS undergoes structural changes during NSC differentiation. The structural changes in CS/DS may be implicated in the regulation of NSC differentiation through interactions with growth/neurotrophic factors and cytokines.

Effects of seat belts worn by pregnant drivers during low-impact collisions

OBJECTIVE

The aim of this study was to understand the injury mechanisms of pregnant drivers and associated fetal outcomes.

STUDY DESIGN

Frontal and rear impact tests using a dummy representing the anthropometry of a pregnant woman were conducted.

RESULTS

In frontal impact tests without a seat belt, abdominal pressure peaked at the point where the dummy contacted the steering wheel. Rear impact tests without a seat belt showed that the dummy moved forward because of rebound and contacted the steering wheel, which was avoided when a seat belt was worn.

CONCLUSION

Wearing a seat belt reduces abdominal pressure or prevents contact with the steering wheel during collisions.

Experimental analysis of the relationship between simulated low-velocity rear-end collisions and fetal outcomes of pregnant rats

Our study aimed to define the risk for a human fetus of rear-end vehicle collisions. We therefore performed drop tests using pregnant SLC Wistar rats. Pressure applied to the rat uterus and rectum at various stages of acceleration was measured. After being dropped, rats were observed throughout pregnancy. At birth, the numbers, weight and the occurrence of physical anomalies among pups were followed-up for 28 days. Uterine pressure increased exponentially from 2.1 +/- 0.3 kPa at 19-fold gravity (G) to 13.9 +/- 0.8 kPa at 92-fold G. These values are much lower than the mechanical failure level of human fetal membrane tissue or of those at risk of adverse fetal outcomes. Neither the average number of offspring per pregnant rat nor the average body weight of newborn pups differed significantly between control pregnant rats and those which had been exposed to acceleration of 46-fold or 92-fold G. Other variables such as maternal mental distress, motion effects of amniotic fluid or seatbelt-induced uterine injuries might contribute to fetal loss.

[Clinical examinations for the traffic accident patients]

Traffic accident is a leading cause of unintentional death and about six-thousands annually died in Japan. As about one-million of persons suffer from traffic injuries, most of them seek medical attention. Therefore, medical staffs have to find the injuries accurately and treat immediately. Furthermore, the cause of accident should also be considered; why the accident was occurred, human error of the driver? To solve these problems, clinical examinations were needed. Medical staffs have to understand the characteristics of the traffic injuries: severe and multiple blunt injuries, popular injuries can be estimated with considering the pattern of the accident. Because some of the accidents are occurred when the driver is under the influence of alcohol and other drugs, screening of these subjects should be performed. Because the public is largely unaware of the preventable nature of traffic injuries, in addition to diagnose and treat accurately, we medical staffs have to attend on the primary prevention of the traffic injuries.

[For the primary prevention of the external causes of deaths]

Recently in Japan, the primary prevention for life-style related disease has been performed based on the comprehensive policies. Although more than 73-thousands of persons have died of external causes (i.e., accident, homicide, suicide), comprehensive preventive measures for them have not been established in Japan. The main objectives of injury research are to prevent the occurrence of injuries and to reduce their level of severity. Therefore, we medical staffs have to solve these problems and attend on the primary prevention of external causes of deaths.

[Suicide due to carbon monoxide poisoning-trends and preventive measures]

To lessen the number of suicide is a nationwide problem in Japan. Recently, suicide due to carbon monoxide poisoning with charcoal burning is increased. The information on this method seems to have spread via suicide-related websites. In addition, there are concerns about drugs and illegal substances that can be bought obtained via the internet. In Japan, the establishment of a voluntary internet guideline in 2005 was effective to save the lives of the persons with suicidal ideations.

Analysis of seating position and anthropometric parameters of pregnant Japanese drivers

OBJECTIVE

An anthropometric study was performed to understand the quantitative characteristics of the seating posture of Japanese pregnant drivers.

METHODS

Twenty pregnant women with a mean gestation of 31.4 +/- 1.9 weeks and 20 age-matched, non-pregnant women provided written informed consent to participate in this study. A mid-sized, sedan-type passenger vehicle was used for measurement. The subjects, wearing light clothing, sat in the driver's seat of the vehicle and fastened the seatbelt after adjusting the seat to their usual driving posture. Longitudinal displacement of the slide adjuster and the reclining angle of the seat back were measured, relative to the reference position. Seating posture was investigated by measuring the coordinates of the anthropometric datum points of the drivers (head, shoulder, hip joint, knee joint, and the clearance between the steering wheel and the upper torso).

RESULTS

The mean horizontal clearance between the lower rim of the steering wheel and the abdomen of the pregnant women was 146 +/- 56 mm, significantly smaller than that of the non-pregnant women (251 +/- 51 mm), due to the protrusion of the abdomen. There was no significant difference in seat adjustment position between the two groups. The height of the pregnant women and the horizontal distance from the lower rim of the steering wheel to the abdomen showed a moderate linear correlation in the pregnant group (R2 = 0.56).

CONCLUSIONS

Compared to previous studies, the differences of longitudinal distance were found between American and Japanese subjects without significant differences of body heights, due to the difference of body weights and abdominal circumferences. This is the first report to analyze the seating position and anthropometric parameters of pregnant drivers in an Asian population.

Sudden death while driving a four-wheeled vehicle: an autopsy analysis

We retrospectively analysed forensic autopsies to resolve various issues associated with sudden natural death while driving. We collected information about the medical history, drug treatment, anthropometry and body mass index (BMI) of 34 individuals who suddenly died of natural causes while driving four-wheeled vehicles. The reasons for driving, details of the vehicle, type of collision, perspective of vehicle behaviour and types of avoidance manoeuvres were also examined. The injury severity score (ISS), the Abbreviated Injury Scale (AIS) and the degree of cardiomegaly of the driver were determined from autopsy findings. The dominant cause of death was ischemic heart disease, which closely agreed with previous findings. However, forensic signs indicated that only 20.6% of deceased drivers had attempted avoidance manoeuvres such as braking or steering before the fatal accident, which contradicts previous findings.

Stereoisomeric Identification of Norephedrine Derived from Methamphetamine or Amphetamine: Urinalysis Results of 33 Methamphetamine Abusers and 1 Amphetamine Abuser in Japan

Stereoisomeric identification of norephedrine (NE) derived from methamphetamine (MA) or amphetamine (AM) was investigated by SIM-GC/MS assay using the urine of 33 MA abusers and 1 AM abuser. The assay simultaneously identified TFA-derivatized MA and AM metabolites, including AM, p-hydroxyl-MA (p-HMA), and p-hydroxyl-AM (p-HAM). The analysis lasted approximately 43 min, with a signal-to-noise ratio of >or=3 and a detection limit of 50 ng/mL. Among 12 urine samples from different subjects, only the S (+) form of MA and its metabolites (AM, p-HMA, p-HAM) was detected, however, a (1R,2S)-(-)-NE stereoisomer was also identified. Among the urine samples of two subjects, only the R (-) form of MA and its metabolites (AM, p-HMA, p-HAM) was detected, while NE was not detected. Following urinalysis of urine obtained from 19 MA abusers and 1 AM abuser, only the (1R,2S)-(-)-NE stereoisomer was identified, while unmetabolized MA, AM, and their metabolites (p-HMA, p-HAM), showed stereoselective metabolism. Although (1R,2S)-(-)-ephedrine (EP) alone was found in the urine of 1 (S)-(+)-MA user and 1 (S)-(+)- and (R)-(-)-MA user among 33 MA users, it was not present in the urine of the remaining 31 subjects. Therefore, (1R,2S)-(-)-NE was likely not of (1R,2S)-(-)-EP origin and was most likely from (S)-(+)-AM of the MA metabolite. The production ratio of (1R,2S)-(-)-NE to (S)-(+)-AM ranged from 0.01 to 0.25 in MA abusers and was 0.12 in AM abusers.

Changes in blood viscosity with the recombinant tissue plasminogen activator alteplase

We measured whole blood viscosity to investigate the time course of the fibrinolytic activity of the recombinant tissue plasminogen activator alteplase. Changes in blood viscosity over time were determined using an oscillation-type viscometer at a shear rate of 400 to 500 per second. Blood viscosity initially increased with alteplase as in untreated blood, but then decreased, reflecting the fibrinolytic activity of generated plasmin. Blood viscosity subsequently stabilized at a level below the initial value owing to the dissolution of both fibrin and fibrinogen by alteplase. To our knowledge, the present study is the first to examine the time course of changes in BV during fibrin formation and degradation. The results indicated that the fibrinolyic agent alteplase might provide the additional benefit of increasing blood flow by lowering blood viscosity.

A Retrospective Analysis of Oral and Maxillofacial Injuries in Motor Vehicle Accidents

PURPOSE

To clarify the relations of the severity of oral and maxillofacial injuries from traffic accidents (TAs) to seating position and the use of restraint systems.

PATIENTS AND METHODS

Hospital records were reviewed for all patients who had sustained oral or maxillofacial injuries in TAs and then were admitted to the Department of Oral and Maxillofacial Surgery, Dokkyo University School of Medicine (Tochigi, Japan), from 1994 through 2003.

RESULTS

A total of 201 patients, with a mean injury severity score (ISS) of 7.9 +/- 7.6, were included in this study. Although patients with any oral or maxillofacial injury with an Abbreviated Injury Scale (AIS) score of 2 or more had extremely low ISSs, hospitalization was relatively long. The ISS and AIS score of the head or neck were significantly higher in unrestrained drivers (12.4 +/- 11.2, 1.2 +/- 1.4, respectively) than in restrained drivers (6.5 +/- 4.6, 0.4 +/- 1.0, respectively). However, AIS scores of the face were similar in unrestrained drivers (1.9 +/- 0.7) and restrained drivers (1.7 +/- 0.5). Furthermore, the incidence of maxillofacial fractures did not differ between the 2 groups.

CONCLUSION

Because wearing seat belts cannot prevent all oral and maxillofacial injuries in motor vehicle occupants, both physicians and engineers must pay greater attention to the mechanisms of oral and maxillofacial injuries in TAs.

Accidental strangulation of a mentally retarded patient by a clothing collar: a case report

A 40-year-old mentally retarded woman died of accidental strangulation in a nursing home. She was found in a kneeling position with her hands on her knees and the collar of her clothing compressing the front and sides of the neck. Before the accident, a nurse had dressed the patient in one-piece overall-style pyjamas put on back to front so that she could not remove the garment herself. The post-mortem findings and reconstruction of the scene of death suggested that the patient had been strangled by the collar of her backward-facing clothing while in a kneeling position. Because patients with psychiatric illnesses may have a limited ability to recognize or communicate symptoms of physical danger, they must be closely monitored by knowledgeable medical and nursing staff. This case highlights the importance of preventing the accidental deaths of mentally retarded patients in nursing homes.

Fungi can be a useful forensic tool

We present a practical case in which the fungi have contributed to the estimation of postmortem interval of the cadaver. A 71-year-old man wearing a shirt and pants was found dead at the bottom of an open well about 6m below the ground in his garden. Externally the face was dotted with colonies of white fungi, which was devoid of dipteran larvae and other insects. The fungi were identified as Penicillium sp. and Aspergillus terrous. These fungi, widely inhabit in the life circumstances, can generally colonize 3-7 days after attaching on the subjects. The appearance of the body surface, the state of decomposition of various organs, police information describing that the man had last been seen 12 days before discovery and the fungal evidence indicated that the man had been dead for about 10 days. We suggest that fungi can provide an useful means of estimating the minimum interval since death when forensic entomology is not applicable. Although, no data about growth rates of the fungi on human cadavers have been available, further researches should be needed to clarify the successive colonization of fungi on human cadavers.