车辆荷载特性影响下的碰撞时间分布规律

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 car-following 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.