Accurate traffic demand estimation is critical for the dynamic evaluation and optimization of signalized intersections. Existing studies based on connected vehicle (CV) data are designed for a single phase only and have not sufficiently studied the real-time traffic demand estimation for oversaturated traffic conditions. Therefore, this study proposes a cycle-by-cycle multi-phase traffic demand joint estimation method at signalized intersections based on CV data that considers both undersaturated and oversaturated traffic conditions. First, a joint weighted likelihood function of traffic demands for multiple phases is derived given real-time observed CV trajectories, which considers the initial queue and relaxes the first-in-first-out assumption by treating each queued CV as an independent observation. Then, the sample size of the historical CVs is used to derive a joint prior distribution of traffic demands. Ultimately, a joint estimation method based on the maximum a posteriori (i.e., the JO-MAP method) is developed for cycle-based multi-phase traffic demand estimation. The proposed method is evaluated using both simulation and empirical data. Simulation results indicate that the proposed method can produce reliable estimates under different penetration rates, arrival patterns, and traffic demands. The feature of joint estimation makes our method less demanding for the penetration rate of CVs and the consideration of prior distribution can significantly improve the estimation accuracy. Empirical results show that the proposed method achieves accurate cycle-based traffic demand estimation with a MAPE of 12.73%, outperforming the other four methods.
翻译:准确的交通需求估算对于信号化十字路口的动态评估和优化至关重要。基于相关车辆数据的现有研究仅设计为单一阶段,没有充分研究过度饱和交通条件的实时交通需求估算。因此,本研究报告提议,基于CV数据,在信号化十字路口采用周期性多阶段交通需求联合估算方法,考虑饱和和和过度饱和交通条件。第一阶段交通需求的联合加权概率功能是实时观测到的CV轨迹,该轨迹认为最初排队和放松第一期的准确假设,将排队的每个排队CV作为独立观察处理。随后,历史CV的抽样规模用于预先联合分配交通需求。最终,基于事后和过度饱和过度饱和的交通需求估算,为基于周期性多阶段的交通需求估算制定了联合估算方法(即JO-MAP方法)。拟议方法是利用模拟和实证数据来评估的。模拟结果显示,将首次排队列的准确度假设和先期假设假设假设,然后将分析每个排队的每期交通需求作为独立观察。拟议的方法的准确性估算,可以显著地显示前期的准确性分析。前期交通需求分析。拟议的C的准确性估算方法可以得出不同的前分析。根据不同的前分析方法得出不同的准确性比率,从而得出不同的准确的准确性估算。预测,可以得出不同的比例,根据不同的前期计算,而得出不同的前期交通需求。预测的准确性估算,根据不同的比例得出不同的前期计算方法,可以得出不同的准确性估算。