基于心理安全距离的行人风险评价及预警算法研究

为实现在机非混行的交通环境下，对动态、随机弱势道路使用者的准确风险评估，基于行车安全场理论提出了考虑行人心理安全距离的碰撞行人风险评价模型。首先通过考虑行驶车辆是否会危及行人的心理安全，提出了心理安全距离的概念，包括心理安全通行距离和心理安全制动距离2个方面，并通过问卷调研挖掘其可能的影响因素进行数值分析；接着将心理安全距离融入行车安全场理论，建立行人风险动态评价模型，并据此提出针对典型行人过街场景的分级预警算法；最后，通过设置PC-Crash仿真试验对预警算法在典型行人过街场景的应用的效果进行分析。研究结果表明：①在无信号灯路段，行人在面对行驶车辆时，所需要的心理安全通行距离不低于50 m，心理安全制动距离一般分布在5~20 m，且车型、行人的性别和年龄等因素都会对心理安全距离数值产生影响；②车辆在分级预警算法作用下，为保证行人心理安全所需要的最小制动减速度分布在0~3 m·s^-2。与现有研究方法对比，该行人预警算法能够在避免事故的同时，有效保证行人的心理安全与车辆驾驶的稳定性，为汽车主动安全预警系统设计提供新的开发视角。

Pedestrian Risk Assessment and Early Warning Algorithm Based on Psychological Safety Distance

To realize an accurate risk assessment of dynamic and random vulnerable road users under the traffic environment of mixed traffic, this paper proposed a pedestrian risk assessment model considering pedestrian psychological safety distance based on the theory of the driving safety field.First, the concept of psychological safety distance, including psychological safety passing distance and psychological safety braking distance, was proposed by considering whether moving vehicles would endanger the psychological safety of pedestrians, and its possible influencing factors were mined through a questionnaire survey for numerical analysis. Then, the psychological safety distance was integrated into the driving safety field theory, and a dynamic evaluation model of pedestrian risk was established.Based on this, a hierarchical early warning algorithm for typical pedestrian crossing scenes was proposed.Finally, the application effect of the early warning algorithm in a typical pedestrian crossing scene was analyzed by carrying outa PC-Crash simulation experiment.The results show that ① on road sections without traffic lights, when pedestrians face a moving vehicle, the required psychological safety travel distance is not less than 50 m, and the psychological safety braking distance is generally distributed between 5 and 20 m. Factors such as vehicle type, pedestrian's gender and age, will all have an impact on the value of psychological safety distance; ② under the action of the hierarchical early warning algorithm, the minimum braking deceleration required to ensure the psychological safety of pedestrians is distributed between 0 and 3 m·s^-2.Compared with existing research methods, the pedestrian early warning algorithm can effectively ensure the psychological safety of pedestrians and stability of driving while avoiding accidents, and can provide a new development perspective for the design of automobile active safety early warning systems.