车辆荷载特性影响下的碰撞时间分布规律

受车辆荷载特性影响的碰撞时间(Time-To-Collision, TTC)，被认为是车辆避撞系统中跟驰过程风险评估的有效指标.本文以车辆类型、超重和超速指标量化表征车辆荷载特性，分解前后车辆不同荷载特性组合的12类跟驰场景.基于动态称重技术获取融合荷载特性的交通流数据，分析车辆荷载特性对自由流交通状态下12类跟驰场景TTC分布的影响，利用KS 检验对比TTC分布的显著性.结果表明：TTC累计频率分布服从指数模型，在5%置信度水平上，跟驰前后车的车辆类型对TTC分布无显著影响；前后车均为超重轻车显著增加了潜在冲突风险，超重增加了轻车跟驰重车，轻车跟驰轻车场景的潜在冲突风险；前后车不超速跟驰场景下，轻车跟驰重车的风险比例高于轻车跟驰轻车.

Effects of Vehicle Load Characteristics on Distributions of Time-to-collision

Time-to-collision (TTC), which is affected by vehicle load characteristics, is considered as an effective index for the risk assessment of the car- following process in collision avoidance systems. This research uses vehicle type, overweight and speeding to quantify vehicle load characteristics. Twelve types of car- following scenarios under free- flow conditions were decomposed with different load characteristics of the leading and following vehicles. The weigh-in-Motion (WIM) technique is applied to obtain traffic flow data that combines the load characteristics. The influence of vehicle load characteristics on TTC distribution in the 12 types of carfollowing scenarios was analyzed. The significance of TTC distribution was compared using KS test. Results show that the distribution of TTC cumulative frequency fits an exponential distribution. At the 5% level of significance, vehicle class and speeding do not show a significant effect on TTC distribution. Overweight of light vehicles has significant effect on TTC distribution. And overweight increases the potential conflict risk in the scenarios of a light vehicle following a heavy/light vehicle. In the case that the leading and following vehicles are not speeding, the potential conflict risk in the scenario of a light vehicle following a heavy vehicle is higher than the scenario of a light vehicle following a light vehicle.