Objectives: Traumatic brain injury（TBI）has a substantial impact on caregivers, and the effects of moderate to severe TBI can be long-lasting or even permanent. This study describes the burden experienced by family caregivers of 344 patients who had suffered traumatic brain injury over 10 years previously. Methods: Family caregivers of the 344 patients who suffered traumatic brain injury 10 years or more previously were asked to fill in an unpublished self-report questionnaire in order to explore their burdens and the patients’ records. Results: In 313 patients（91.0％）, loss of consciousness after injury continued for over 4 days. Of the total 344 patients（289 male and 55 female; current age: 43.6±12.3 years old; age at injury: 24.0±13.3 years old）, 296 （86.0％）lived with a parent. Family burden was found to be associated with increased cognitive, emotional, and behavioral disorders of TBI patients（correlation coefficient＝0.61）. Most patients（78.5％）were independent in the activities of daily living（ADL）, and no statistically significant difference was found between family burden and ADL abilities of TBI patients（correlation coefficient＝－0.18）. Of the 344 patients, 220 were employed, including welfare employment（53.6％）. The non-employment group demonstrated more considerable feeling of burden to family than the employment group（p＜0.01）. Conclusions: The feeling of burden to family is immense even now, after more than 10 years since the accident. The feeling is much influenced by cognitive, emotional, and behavioral disorders as TBI sequelae that are caused by frontal damage, and psychosocial problems after injury. Furthermore, the employment situation of patients is also an important factor for the feeling of burden of long-term care. In Japan, the length of hospital stay cannot exceed more than six months after injury by law. Therefore, it is necessary to focus medical intervention for an outpatient on psychosocial problems, and if possible, vocational rehabilitation is necessary for moderate to severe TBI patients, as part of community rehabilitation.

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In this research, we focus on the automated driving system of level 4 defined in SAE. The system has not been needed to monitor by the drivers in limited area such as a highway, and the drivers can take enough sleep in the vehicle when the system drives a highway. On the other hand, the drivers needs to take over driving operation from the system appropriately when the drivers drive in city roads. However, it is difficult for driver who just awake from sleeping have slower response than awake state, and the driver cannot drive safely. The purpose of this study is to consider the stimulation time by arousal method（④）for drivers who have slept well on highways using automated driving system of level 4 to take over the driving operation safely from the system. For this reason, we conducted experiments targeting automated driving system of level 4defined in SAE this study. In the experiment scenario, first, the drivers take enough sleep while driving on the left lane of the highway by the automated driving system. Second, the automated driving system warns driver and wakes up the driver in the vicinity of a highway exit. Third, the drivers take over the driving operation from the automated driving system. Finally, the drivers drive city road and perform a brake operation in order to avoid a pedestrian who are rushing out from the blind spot of the stopped track. As an arousal method of the drivers, we give the drivers two stimuli. The first stimulus is an air conditioner blow, and second stimulus is seat vibration. The driver's stimulation time is 2 minutes or 5 minutes. Since this verification is extremely high in the risk of collision accident, the experiment was conducted using the driving simulator to consider safety of some participants. As the result of experiment, by giving a stimulus to the driver for 5 minutes, we obtain the driver who just awake from sleeping can perform the driving operation with the same reaction time and same brake pedal force as that at the time of awakening. We clarified that the drivers who just awake from sleeping can take over driving operation from automated driving system same as in awake state by giving a stimulus to the driver for 5 minutes.

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We examined motor vehicle–pedestrian collisions occurring between 2012 and 2016 in Japan, focusing on collisions in which pedestrians were lying on the road before the collision. The background of the collision, injury severity and outcomes for the pedestrian were investigated retrospectively using a database from the Institute for Traffic Accident Research and Data Analysis, Japan. The database contained 28,683 pedestrian casualties and 7,256 fatalities. Of these, 0.6％ of the casualties and 8.3％ of the fatalities involved pedestrians who were lying on the road. Collisions with pedestrians lying on the road occurred more frequently in winter and summer, and at weekends and night times, unlike other types of collisions （p ＜0.001）. The rates of fatalities and severe injuries were significantly higher for pedestrians who were lying on the road compared with those who were not （33.0％ vs. 2.3％, 30.8％ vs. 15.5％, respectively）. To reduce fatal vehicle to pedestrian collisions, it is important to identify accidents involving pedestrians lying on the road in each region. This could inform the development of safety systems for avoiding collisions with pedestrians lying on the road.

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Other than vehicle collisions, causes of death in vehicle passengers include carbon monoxide （CO） poisoning, heatstroke and drowning. However, there are no statistics available on these issues, so no effective preventive measures have been put in place. We collected reports of autopsies on cases of accidental CO poisoning from April 2014 to March 2019 and reviewed the literature on this issue to 2018 in Japan. Three autopsies from two accidents were examined. One accident was caused by obstruction of the exhaust tail pipe by snow, and the other by damage to the exhaust tail pipe after a collision. The literature review found 39 cases of accidental CO poisoning in automobiles reported in Japan, of which 14 were fatal. In total, 42.9％ of the fatal cases, and 8.0％ of the non-fatal cases were caused by poor vehicle maintenance, and 21.4％ of the fatal cases and 92.0％ of the non-fatal cases by obstruction of the exhaust tail pipe by snow. To prevent CO poisoning, it is therefore necessary to raise awareness of the danger of this issue, and the importance of regular vehicle inspections and maintenance to identify any damage to the exhaust pipe. People should also be reminded of the importance of removing snow from around the exhaust tail pipe before starting the engine. The cases we reviewed might be limited, so we suggest that it may be helpful to register all CO poisoning relating to motor vehicles. This would allow nationwide analyses to be carried out. In future, it may be necessary to develop a CO warning system for vehicles.

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In the transportation industry, it is difficult to maintain the drivers’ daily rhythm due to their work style （long driving duties and various work shifts）. Driving in a drowsy state may cause serious accidents and it is necessary to take countermeasures to prevent them. Food containing asparagus extract has been reported to adjust sleep-wake rhythm and improve alertness upon awakening. Therefore, we examined the effects of the food containing asparagus extract on sleep state, fatigue, and safe driving in taxi drivers. With the cooperation of Fuji taxi group based in Aichi Prefecture, we enrolled 76 taxi drivers as subjects and conducted a four-week intervention. The subjects were divided into two groups: an active group （with test food intake） and a control group （without test food intake）, and the sleep state, fatigue, and status of safe driving were evaluated from before intake to 4 weeks after intake. We found that, the sleep time as evaluated by St Mary’s Hospital Sleep Questionnaire increased significantly in the active group compared to the control group, and the sleepiness as evaluated by Karolinska Sleepiness Scale and the fatigue feeling as evaluated by Chalder Fatigue Scale also decreased significantly. In addition, alertness upon awakening and the frequency of sleepiness during work had improved, suggesting that the intake of the test food had a beneficial effect on the improvement of sleep quality and fatigue in taxi drivers. We objectively evaluated the status of safe driving using a drive recorder and found that the number of sudden accelerations had decreased, suggesting that improvement of sleep by taking the test food may contribute to safe driving. At present, only limited methods such as cognitive behavioral therapy can be used to improve sleep, but this result shows that food containing asparagus extract can also be used as a countermeasure. Improving sleep quality using food could serve as an alternative option for maintaining drivers’ health and for promoting management of driver health in transportation companies.

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Among all traffic-related deaths, several percent are reportedly regarded as intentional in foreign countries. Particularly, cases of collisions of passenger cars with large trucks are often likely to be cases of suicide. This retrospective survey of forensic autopsy files was conducted at our department to identify intentional collisions among cases of vehicles entering an opposing lane of traffic, resulting in collisions with oncoming vehicles. During the 17 years of 2002–2018, a total of 193 autopsy cases in the Department of Forensic Medicine, Tokai University School of Medicine, were road-traffic related. As road users, motor vehicle drivers, specifically excluding bicyclists, accounted for 81 of the victims. In those cases, 11 were killed by head-on collisions in the oncoming lane, one of whom was judged as suicide based on circumstances including eyewitness information. Three cases were associated with antidepressant treatment, heavy drinking, and drug abuse, and were suspected as cases of intentional collision. Collectively, these four cases were of three men and one woman in their forties or fifties who drove passenger cars. The associated vehicles were one compact passenger car, one wagon, and two trucks. Results support the conjecture that some motor vehicle collisions are intended as suicide. Such suicidal cases on roads are specified in traffic statistics in foreign countries, but they are not differentiated in statistics for Japan. Because the relative percentages of suicides and natural deaths are increasing in other countries, Japan might be experiencing similar trends. Detailed investigations of fatal traffic accidents are necessary, particularly of head-on collisions with motor vehicles.

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