城市快速路异常事件发生频率的时间差异性分析

城市快速路系统长时间处于高流量高密度状态时,异常事件等小的扰动就可能引发较大规模的拥堵.根据连接路段的匝道类型对路段进行分类,利用上海市内环和中环浦西段一年的异常事件监控数据,分析了不同路段上异常事件发生频率的月变、周变与时变特征,并分别探讨了抛锚和碰撞两类异常事件与交通流特征的关系.运用负二项回归建立了异常事件发生频率基于时间差异性的估计模型.分析发现,公休日变量估计结果显著,温度只对抛锚类事件产生明显影响,天气状况对不同快速路、不同时间段和不同事件的影响显著性有较大差异.

Temporal Heterogeneity Analysis for Incident Frequency on Urban Expressways

Incidents on congested expressways lead to roadway capacity reduction and commuter time loss. Incident data of Shanghai inner ring and middle ring expressways in Puxi Area by video monitoring were employed in this study. An analysis was made of the monthly change, weekly change and daily change of incident occurrence on segments with different ramp types, and the relationship was explored between the incident occurrence and traffic flow characteristics. Negative binomial regression was adopted to establish the frequency estimation model to explore temporal heterogeneity. Results show that holiday is significant for both types of incidents while temperature only has a significant impact on disabled vehicles. The effect of weather varies much among different expressways, time periods and incident types.