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REDUCTION IN THE HEAD INJURY LEVEL DUE TO JUNIOR HIGH SCHOOL CYCLISTS WEARING HELMETS
Yasuhiro Matsui,Shoko Oikawa 한국자동차공학회 2018 International journal of automotive technology Vol.19 No.6
We assessed the effect of wearing a junior-high-school helmet when the frontal or lateral part of a helmet impacted the upper part and lower part of the A-pillar of a vehicle at 35 km/h (212 J). The head injury criterions (HICs) of the headform impactor without a helmet were respectively 4530 and 4937. In the case of the headform impactor wearing a junior-high-school helmet, the helmet reduced the HIC by 17.5 % and 9.9 % for impacts of the frontal part of the helmet and by 15.0 % and 4.0 % for impacts of the lateral part of the helmet. We also assessed the effect of wearing a junior-high-school helmet when the frontal part of the helmet impacted a road surface from a height of 1.5 m (66 J). The HIC of the headform impactor without a helmet was 6525. The HIC was reduced by 82.7 % when wearing a junior-high-school helmet. Both experiments show that, under a relatively low impact energy condition such as a road surface impact, wearing a junior-highschool helmet greatly reduces the head injury level. Meanwhile, under a relatively high-impact-energy condition such as impact against an A-pillar, wearing a junior-high-school helmet is ineffective in reducing the head injury level.
Yasuhiro Matsui,Masami Kubota,Shoko Oikawa 한국자동차공학회 2018 International journal of automotive technology Vol.19 No.1
The Japan New Car Assessment Program (J-NCAP) evaluates the performance of cars in terms of protection against whiplash injuries in rear-end collisions. In the test protocol, a simplified triangular acceleration is applied to the sled. This study clarifies whether biofidelic rear-impact dummy II (BioRID II) measurements obtained for simplified triangular acceleration reflect car-to-car rear-end impacts in real-world accidents in Japan. We conducted a car-to-car rear-end impact experiment and a simplified-triangular-acceleration sled test. Our results indicate that the time series of dummy responses were approximately consistent in the two test conditions. The neck injury criterion (NIC) and maximum acceleration of the head and T1 measured using the BioRID II dummy were similar in the car-to-car and sled experiments. This revealed that the J-NCAP test protocol using simplified triangular acceleration reflects the car-to-car rear-end impact experiment using Japanese cars, in terms of the NIC and maximum acceleration of the head and T1.
Features of Fatal Truck Accidents Compared with Sedans
Oikawa Shoko,Matsui Yasuhiro,Kubota Naoyuki,Aomura Shigeru,Sorimachi Kazuhiro,Imanishi Akira,Fujimura Takeshi 한국자동차공학회 2021 International journal of automotive technology Vol.22 No.4
This study clarified the features of fatal truck–pedestrian and truck–cyclist accidents by a comparison with sedans. Fatal accident data from the Japanese Institute Traffic Accident Research and Data Analysis (ITARDA) database were analyzed for the years 2012 ~ 2016. The trucks were classified into three categories: heavy-, medium-, and light-duty. All three categories had higher percentages of pedestrians as fatal collision partners as opposed to cyclists. Every truck category had significantly higher percentages of pedestrian fatalities due to daytime right turns than sedans. Heavy-duty trucks had significantly higher percentages of cyclist fatalities due to daytime and nighttime left turns than sedans. These results show that the design specifications for new sensing technology to avoid collisions with pedestrians and cyclists should differ among vehicle types. The knowledge obtained in this study will be useful to develop new technology or systems that are effective in dangerous situations between trucks and pedestrians or cyclists.
FACTORS IN FATAL INJURIES TO CYCLISTS IMPACTED BY FIVE TYPES OF VEHICLES
Shoko Oikawa,Yasuhiro Matsui,Hiromichi Nakadate,Shigeru Aomura 한국자동차공학회 2019 International journal of automotive technology Vol.20 No.1
The factors in fatal injuries to cyclists in collisions with five different types of vehicles were examined using data from the Institute for Traffic Accident Research and Data Analysis in Japan for the period 2004 ~ 2013. The vehicle types were sedans, minivans, box vans, light passenger cars (LPCs), and light cargo vans (LCVs). The analyses focused on cyclist age, gender, main body regions that suffered fatal injuries, and vehicle travel speeds. Cyclists aged 75+ years made up the largest group of fatalities in collisions with sedans, box vans, LPCs, and LCVs, whereas those aged 13 ~ 64 years made up the largest group of fatalities in collisions with minivans. Head injuries were the most frequent injuries in cyclist fatalities. The percentage of head injuries in fatalities of cyclists aged 75+ years was significantly higher than that for cyclists aged 13 ~ 64 years for box vans, but significantly lower for sedans, LPCs, and LCVs. For sedans, the percentage of hip injuries in fatalities of cyclists aged 75+ years was significantly higher than that of cyclists aged 13 ~ 64 years. Cyclist fatalities due to hip injuries were significantly more common for females than for males in collisions with sedans, LPCs, and LCVs.
Oikawa Shoko,Matsui Yasuhiro,Kubota Naoyuki,Aomura Shigeru,Sorimachi Kazuhiro,Imanishi Akira,Fujimura Takeshi 한국자동차공학회 2023 International journal of automotive technology Vol.24 No.2
This study attempts to clarify the characteristics of light-duty truck collision accidents involving pedestrians during right-turn maneuvers by analyzing actual pedestrian accident data in Japan. Evidence differences were observed between the daytime and nighttime. The number of injured and fatal pedestrians during the day was larger than that during the night. The rate of vehicle travel velocity ≤ 10 km/h in the daytime (47.0 %) was significantly higher than that in the nighttime (39.2 %), whereas the rate of vehicle travel velocity ≤ 20 km/h in the nighttime (52.7 %) was significantly higher than that in the daytime (46.9 %). The highest rate in the daytime was presented for the age group of 13 ~ 64 years in minor injuries (54.1 %) and for those 75 years or older in serious injuries (47.5 %) and fatalities (64.3 %). For pedestrian crossing directions on the crosswalk, the pedestrian crossing from the forward left-side corner to the right-side corner exhibited the highest percentage in the daytime (39.2 %), and the opposite direction of crossing from the right-side corner to the forward left-side corner exhibited the highest percentage in the nighttime (39.6 %). The characteristics obtained in this study will contribute to the development and evaluation of advanced safety systems that are specialized for right-turning maneuvers of light-duty trucks.
Namihira, Tomoyuki,Shinzato, Naoya,Akamine, Hikaru,Nakamura, Ichiro,Maekawa, Hideaki,Kawamoto, Yasuhiro,Matsui, Toru Asian Australasian Association of Animal Productio 2011 Animal Bioscience Vol.24 No.3
To investigate the effect of nitrogen fertilization on the quality of tropical grass silage, guinea grass grown with 3 types of nitrogen fertilizers, namely, urea, ammonium sulfate, and compound fertilizer 804, at 2 fertilization levels, 0.5 and 2.5 kg $Na^{-1}$ (0.5 N and 2.5 N, respectively), was subjected to silage fermentation. Silage fertilized with 0.5 N showed butyrate-dominant fermentation, irrespective of the type of fertilizer used. On the other hand, fermentation of silage fertilized with 2.5 N was significantly affected by the type of fertilizer used; fertilization with ammonium sulfate and compound fertilizer 804 resulted in silage that contained a large amount of butyrate and no lactate; this silage was considered to be of a significantly low quality as compared with silage fertilized with 0.5 N. Among silage fertilized with 2.5 N, the desirable butyrate-free fermentation was found only in urea-fertilized silage, which had the best quality. Grass material fertilized with a high level of urea accumulated a relatively high concentration of nitrate nitrogen (0.22% dry matter). Our results presented here suggest that nitrogen fertilizer management could affect the quality of tropical grass silage and that a relatively high concentration of nitrate in silage may promote butyrate-free fermentation even in tropical grass silage.