Assessment of the effect of motorcycle autonomous emergency braking (MAEB) based on real-world crashes

<b>Objective:</b> Vehicles are increasingly being equipped with Autonomous Emergency Braking (AEB) and literature highlights the utility to fit a similar active safety system in Powered Two-Wheelers (PTWs). This research attempts to analyze the efficacy of PTW Autonomous Emergency Braking (MAEB) when functioning solely, and in the case where both the PTW and Opponent Vehicle (OV) have AEB installed. <b>Methods:</b> 23 crashes involving motorcyclists that occurred in metropolitan areas of Italy between 2009 and 2017 were selected. The “In-depth Study of road Accidents in FlorencE (InSAFE)” provides data for the study. Each crash was reconstructed in PC-Crash 12.1 software. The obtained simulation of the crash dynamics was then used to create the dataset of cases fitted with AEB and MAEB systems. A custom MAEB system was implemented with specifications based on literature. <b>Results:</b> The majority of crashes occurred on urban roads, at intersections, on dry asphalt, with clear visibility, and in daylight. The passenger vehicle was the most frequent opponent vehicle (70%). Almost half the sample involved the PTW rider traveling beyond the speed limit permitted on urban roads. MAEB was found to be applicable in 19 out of 23 real-world crashes allowing the avoidance of two crashes with the progressive triggering criteria (Time to Collision (TTC) − 1.0 s) and one crash in the case where both the PTW and OV have AEB installed with more conservative setups. MAEB simulations show important trends in the reduction of the PTW impact speed (ISR) from the conservative (TTC-0.6s) to standard (TTC-0.8s) to progressive (TTC-1.0s) triggering criteria. The mean impact speed reduction (ISR) becomes 8.6 km/h, 13.8 km/h, 19.1 km/h, respectively. <b>Conclusions:</b> The results suggested that MAEB may be extremely effective in the PTW impact speed reduction and that an earlier MAEB intervention is beneficial in achieving higher reductions in the PTW impact speed. Further, the effect of opponent vehicles also possessing AEB was studied, and it was found that this increased the likelihood of crash avoidance and greater reduction in crash severity in unavoidable circumstances.

<b>研究目标：</b> 当前车辆越来越多地配备自动紧急制动系统（Autonomous Emergency Braking, AEB），现有文献证实，为动力两轮车（Powered Two-Wheelers, PTWs）加装同类主动安全系统具备实用价值。本研究旨在分析动力两轮车自主紧急制动系统（PTW Autonomous Emergency Braking, MAEB）单独运行时的效能，以及动力两轮车与对方车辆（Opponent Vehicle, OV）均搭载自动紧急制动系统场景下的系统表现。<b>研究方法：</b> 本研究选取2009年至2017年间意大利大都市区发生的23起涉及摩托车骑手的碰撞事故，数据来源于“佛罗伦萨道路事故深度研究（In-depth Study of road Accidents in FlorencE, InSAFE）”。所有事故均通过PC-Crash 12.1软件进行事故重构，基于得到的碰撞动力学仿真结果，构建了搭载AEB与MAEB系统的事故数据集。本研究基于现有文献的参数规格，实现了一套自定义MAEB系统。<b>研究结果：</b> 多数事故发生于城市道路的交叉口，路面为干燥沥青，能见度良好且为白天时段。乘用车是最常见的对方车辆（占比70%）。近半数样本中，摩托车骑手的行驶速度超过了城市道路限速。研究发现，23起真实事故中有19起可通过MAEB系统发挥作用，其中采用渐进式触发准则（碰撞时间（Time to Collision, TTC）−1.0s）时可规避2起碰撞；当动力两轮车与对方车辆均搭载自动紧急制动系统且采用更为保守的设置时，可规避1起碰撞。MAEB仿真结果显示，随着触发准则从保守型（TTC−0.6s）到标准型（TTC−0.8s）再到渐进型（TTC−1.0s）逐步变化，动力两轮车的碰撞速度降低量（Impact Speed Reduction, ISR）呈现出显著的变化趋势，平均碰撞速度降低量分别可达8.6km/h、13.8km/h和19.1km/h。<b>研究结论：</b> 结果表明，MAEB可有效降低动力两轮车的碰撞速度，且更早的MAEB干预能够实现更高的碰撞速度降幅。此外，本研究还探究了对方车辆搭载自动紧急制动系统的影响，发现在不可避免发生碰撞的场景中，该系统可提升碰撞规避概率，并进一步降低碰撞严重程度。