高速公路车辆排队尾部交通事故时空分布特征

根据高速公路常发拥堵路段的交通流数据, 采用累计占有率法绘制交通流占有率波动曲线, 用来判断拥堵路段内车辆排队尾部轨迹, 分析了占有率、里程位置、时间间隔的关系, 确定了累计占有率曲线的拐点。分析了排队传播、消散过程中交通事故频数与时间、空间距离的关系, 对分布特征进行了统计分析。分析结果表明: 车辆在时间和空间上接近排队车辆尾部时, 发生交通事故的频数明显增加, 时间距离与空间距离以排队尾部为中心呈现正态分布, 不同行驶方向路段内正态分布曲线不存在显著差异, 但拥堵传播与消散过程的正态分布曲线存在显著差异。建立的事故发生概率的联合正态分布模型, 可用于预测排队车辆尾部附近的交通事故风险, 为实施动态交通控制以提高快速道路交通安全提供理论依据。

Spatial and temporal distribution characteristics of traffic accident for highway vehicle queue tail

Based on the traffic flow data of recurrent congestion section on highway, the cumulative occupancy method was used to draw the fluctuating curve of traffic flow occupancy, which was used to judge the trajectory of vehicle queue tail at congestion section.The relations among occupancy, mileage position and time interval were analyzed.The inflection point of cumulative occupancy curve was determined.For the queue propagating and dissipating processes, the relations between traffic accident frequencies and temporal and sptial distances were analyzed, and the distribution features were statistically studied.Analysis result shows that when vehicle temporally and spatially approaches the queue tail, the occurrence frequency of traffic accident obviously increases, and the temporal distance and spatial distance follow the normal distribution centered on the queue tail.Normal distribution curves in different driving directions have no significant differences, but have significant differences between congestion propagation and dissipation processes.The developed joint normal distribution model of traffic accident occurring probability can be used to predict the traffic accident risks in the vicinity of queue tail, and to provide the theoretical foundation for applying dynamic traffic control for improving highway safety.