Ekambaram Karthikeyan, Frampton Richard, Bartlett Lisa
a Loughborough University , Leicestershire , UK.
Traffic Inj Prev. 2015;16 Suppl 2:S77-86. doi: 10.1080/15389588.2015.1064528.
To determine whether varying the seat belt load limiter (SBL) according to crash and occupant characteristics could have real-world injury reduction benefits in frontal impacts and, if so, to quantify those benefits.
Real-world UK accident data were used to identify the target population of vehicle occupants and frontal crash scenarios where improved chest protection could be most beneficial. Generic baseline driver and front passenger numerical models using a 50th percentile dummy were developed with MADYMO software. Simulations were performed where the load limiter threshold was varied in selected frontal impact scenarios. For each SBL setting, restraint performance, dummy kinematics, and injury outcome were studied in 5 different frontal impact types. Thoracic injury predictions were converted into injury probability values using Abbreviated Injury Scale (AIS) 2+ age-dependent thoracic risk curves developed and validated based on a methodology proposed by Laituri et al. (2005). Real-world benefit was quantified using the predicted AIS 2+ risk and assuming that an appropriate adaptive system was fitted to all the cars in a real-world sample of recent frontal crashes involving European passenger cars.
From the accident data sample the chest was the most frequently injured body region at an AIS 2+ level in frontal impacts (7% of front seat occupants). The proportion of older vehicle front seat occupants (>64 years) with AIS 2+ injury was also greater than the proportion of younger occupants. Additionally, older occupants were more likely to sustain seat belt-induced serious chest injury in low- and moderate-speed frontal crashes. In both front seating positions, the low SBL provided the best chest injury protection, without increasing the risk to other body regions. In severe impacts, the low SBL allowed the driver to move dangerously close to the steering wheel. Compared to the driver side, greater ride-down space on the passenger side gave a higher potential for using the low SBLs. When applying the AIS 2+ risk reduction findings to the weighted accident data sample, the risk of sustaining an AIS 2+ seat belt injury changed to 0.9, 4.9, and 8.1% for young, mid, and older occupants, respectively, from their actual injury risk of 1.3, 7.6, and 13.1%.
These results suggest the potential for improving the safety of older occupants with the development of smarter restraint systems. This is an important finding because the number of older users is expected to increase rapidly over the next 20 years. The greatest benefits were seen at lower crash severities. This is also important because most real-world crashes occur at lower speeds.
确定根据碰撞和驾乘人员特征改变安全带负载限制器（SBL）是否能在正面碰撞中切实降低伤害，如果可以，则量化这些益处。
利用英国真实事故数据确定车辆驾乘人员的目标群体以及改善胸部保护可能最有益的正面碰撞场景。使用MADYMO软件开发了采用第50百分位假人的通用基线驾驶员和前排乘客数值模型。在选定的正面碰撞场景中对负载限制器阈值进行变化的情况下进行模拟。对于每个SBL设置，在5种不同的正面碰撞类型中研究约束性能、假人运动学和伤害结果。使用基于Laituri等人（2005年）提出的方法开发并验证的简略损伤量表（AIS）2 +年龄相关胸部风险曲线，将胸部损伤预测转换为损伤概率值。使用预测的AIS 2 +风险并假设在涉及欧洲乘用车的近期正面碰撞的真实样本中所有汽车都安装了合适的自适应系统，来量化实际益处。
从事故数据样本来看，在正面碰撞中，胸部是AIS 2 +级最常受伤的身体部位（前排座位驾乘人员的7%）。年龄较大的车辆前排驾乘人员（>64岁）AIS 2 +损伤的比例也高于较年轻驾乘人员的比例。此外，在低速和中速正面碰撞中，年龄较大的驾乘人员更有可能遭受安全带导致的严重胸部损伤。在两个前排座位位置，低SBL提供了最佳的胸部损伤保护，而不会增加对其他身体部位的风险。在严重碰撞中，低SBL会使驾驶员危险地靠近方向盘。与驾驶员一侧相比，乘客一侧更大的下沉空间为使用低SBL提供了更高的可能性。当将AIS 2 +风险降低结果应用于加权事故数据样本时，年轻、中年和老年驾乘人员遭受AIS 2 +安全带损伤的风险分别从其实际损伤风险的1.3%、7.6%和13.1%变为0.9%、4.9%和8.1%。
这些结果表明，随着更智能的约束系统的开发，有可能提高老年驾乘人员的安全性。这是一项重要发现，因为预计在未来20年老年用户数量将迅速增加。在较低碰撞严重程度下能看到最大益处。这也很重要，因为大多数实际碰撞发生在较低速度下。
