Diversion area lane speed characteristics.

The short-distance continuous diversion area plays a crucial role within mountainous urban expressway systems, significantly enhancing the efficiency of specialized road sections through capacity analysis. This study develops a capacity calculation model tailored to the diversion area’s unique characteristics and principal capacity-influencing factors. Initially, the research focuses on a specific short-distance continuous diversion area of a mountainous urban expressway, employing video trajectory tracking technology to gather trajectory data. This data serves as the basis for analyzing road and traffic characteristics. Subsequently, the model computes the capacity influenced by eight variables, including diversion point spacing and deceleration lane length, using VISSIM simulation experiments. A gray correlation analysis identifies key factors, which guide the establishment of the model’s fundamental structure through two-factor surface fitting results. Mathematical statistical methods are then applied to resolve the model’s parameters, culminating in a robust capacity calculation model. The findings reveal that diversion point spacing, along with primary and secondary diversion ratios, significantly influence capacity. Notably, the capacity exhibits a marked quadratic polynomial relationship with the primary diversion ratio and diversion point spacing, and a linear relationship with the secondary diversion ratio. The model’s validity is confirmed through a case study at the diversion area north of Huacun Interchange in Chongqing Municipality, where the discrepancy between calculated and actual capacities is under 5%, underscoring the model’s high accuracy. These results offer valuable theoretical and methodological support for the planning, design, and traffic management of diversion areas.

短距离连续分流区在山地城市快速路系统中发挥着至关重要的作用，通过通行能力（capacity）分析可显著提升特定路段的运行效率。本研究针对分流区的独特特性与主要通行能力影响因素，构建了专属的通行能力计算模型。首先，研究以某山地城市快速路的特定短距离连续分流区为研究对象，采用视频轨迹追踪技术采集轨迹数据，并以此为基础开展道路与交通特性分析。随后，本研究借助VISSIM仿真实验，针对分流点间距、减速车道长度等8个影响变量，计算得到通行能力。通过灰色关联分析（gray correlation analysis）识别关键影响因素，并结合双因素曲面拟合结果确定模型的基本架构。随后运用数理统计方法求解模型参数，最终得到性能可靠的通行能力计算模型。研究结果表明，分流点间距、主分流比与次分流比均对通行能力存在显著影响。值得注意的是，通行能力与主分流比、分流点间距呈现显著的二次多项式关系，而与次分流比则呈线性关系。通过重庆市华村立交北侧分流区的案例验证，模型计算值与实际通行能力的偏差不足5%，充分证明了模型的高精度性。本研究成果可为分流区的规划、设计与交通管理提供极具价值的理论与方法支撑。