快速路出口匝道衔接段交通特性与安全分析

为了探究快速路出口匝道与下游交叉口衔接段的驾驶行为与安全特性，结合实测换道车辆轨迹数据，分析匝道衔接段车辆轨迹特性和换道位置特性. 利用交通冲突技术，以后侵入时间（PET）为指标对车辆换道风险展开分析，建立有序概率模型识别冲突严重程度的影响因素. 结果显示，用Lorentz分布模型拟合车辆换道位置效果较好，换道类型与跨越车道数对车辆换道位置有显著影响，在强制换道与跨越多车道时换道位置更靠近衔接段始端；相较于普通衔接段，匝道衔接段行车风险更高，主要冲突类型为交叉冲突；衔接段饱和度、换道位置、交叉冲突、强制换道以及违章换道与冲突严重程度显著相关. 匝道衔接段释放车辆的车头时距稳定性差，交织区排队车辆的释放受换道干扰严重.

Traffic characteristics and safety analysis of expressway off-ramp junction

In order to explore the driving behavior and safety characteristics of the junction between the off-ramp and the downstream intersection, combined with the measured track data of lane changing vehicles, the track characteristics and the lane changing position characteristics of the ramp junction vehicles were analyzed. Using the traffic conflict technology, the risk of vehicle lane changing was analyzed with post encroach time (PET) as the index, and the ordered probability model was established to identify the factors affecting the severity of the conflict. Results show that the Lorentz distribution model can be used to fit the vehicle lane change position. The lane change type and the number of lane crossing have significant effects on the vehicle lane change position, and the lane change position is closer to the beginning of the junction when the lane change is forced and the lane crossing is multi-lane. Compared with the ordinary junction section, the driving risk of the ramp junction section is higher, and the main conflict type is crossover conflict. The saturation of junction section, lane change position, cross conflict, forced lane change and illegal lane change are significantly related to the severity of conflict. The stability of the headways in the off-ramp junction section is poor during the green phase, and the lane changing interference of the queuing vehicle in the interweaving section is serious.