a Univ Lyon, Université Lyon 1, IFSTTAR, UMRESTTE UMR_T 9405 , Lyon , France.
Traffic Inj Prev. 2018 Jan 2;19(1):94-101. doi: 10.1080/15389588.2017.1332408. Epub 2017 May 30.
The present study estimates pedestrians' risk of death according to impact speed when hit by a passenger car in a frontal collision.
Data were coded for all fatal crashes in France in 2011 and for a random sample of 1/20th of all road injuries for the same year and weighted to take into account police underreporting of mild injury. A cloglog model was used to optimize risk adjustment for high collision speeds. The fit of the model on the data was also improved by using the square of the impact speed, which best matches the energy dissipated in the collision.
Modeling clearly demonstrated that the risk of death was very close to 1 when impact speeds exceeded 80 km/h. For speeds less than 40 km/h, because data representative of all crashes resulting in injury were used, the estimated risk of death was fairly low. However, although the curve seemed deceptively flat below 50 km/h, the risk of death in fact rose 2-fold between 30 and 40 km/h and 6-fold between 30 and 50 km/h. For any given speed, the risk of death was much higher for more elderly subjects, especially those over 75 years of age. These results concern frontal crashes involving a passenger car. Collisions involving trucks are far less frequent, but half result in the pedestrian being run over, incurring greater mortality.
For impact speeds below 60 km/h, the shape of the curve relating probability of death to impact speed was very similar to those reported in recent rigorous studies. For higher impact speeds, the present model allows the curve to rise ever more steeply, giving a much better fit to observed data. The present results confirm that, when a pedestrian is struck by a car, impact speed is a major risk factor, thus providing a supplementary argument for strict speed limits in areas where pedestrians are highly exposed.
本研究根据行人在正面碰撞中被乘用车撞击时的撞击速度来估计行人的死亡风险。
对 2011 年法国所有致命碰撞事故的数据进行编码，并对同年所有道路伤害的 1/20 随机样本进行编码，并加权以考虑警方对轻伤的漏报。使用 cloglog 模型来优化对高碰撞速度的风险调整。通过使用撞击速度的平方来改善模型对数据的拟合，这最能匹配碰撞中消耗的能量。
模型清楚地表明，当撞击速度超过 80 公里/小时时，死亡风险非常接近 1。对于速度低于 40 公里/小时的情况，由于使用了代表所有导致受伤的碰撞的数据，因此估计的死亡风险相当低。然而，尽管在 50 公里/小时以下的曲线看起来似乎很平坦，但实际上，死亡风险在 30 至 40 公里/小时之间增加了两倍，在 30 至 50 公里/小时之间增加了六倍。对于任何给定的速度，死亡风险对于年龄较大的人来说更高，特别是那些 75 岁以上的人。这些结果涉及涉及乘用车的正面碰撞。涉及卡车的碰撞频率要低得多，但有一半会导致行人被碾压，死亡率更高。
对于低于 60 公里/小时的撞击速度，与撞击速度相关的死亡概率曲线的形状与最近的严格研究报告非常相似。对于更高的撞击速度，本模型允许曲线上升得更陡峭，从而更能适应观察到的数据。本研究结果证实，当行人被汽车撞击时，撞击速度是一个主要的风险因素，因此为在行人高度暴露的区域严格限速提供了一个补充论据。
