Stochastic cell transmission model (SCTM): A stochastic dynamic traffic model for traffic state surveillance and assignment
Stochastic cell transmission model (SCTM): A stochastic dynamic traffic model for traffic state surveillance and assignment
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DOI：
10.1016/j.trb.2010.09.006
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发表时间：
2011-03
影响因子：
6.8
通讯作者：
A. Sumalee;R. Zhong;T. Pan;W. Y. Szeto
中科院分区：
文献类型：
--
作者：
A. Sumalee;R. Zhong;T. Pan;W. Y. Szeto
本文提出了一种一阶宏观随机动态交通模型，即随机单元传输模型（SCTM），用于对具有随机需求和供给的高速公路路段上的交通流密度进行建模。 SCTM由五种运行模式组成，对应高速公路路段的不同拥堵程度。每种模式都被表述为离散时间双线性随机系统。提出了一组概率条件来表征每种模式发生的概率。五种模式的总体效果是通过联合交通密度来估计的，该密度是根据有限混合分布理论推导出来的。 SCTM 不仅捕获交通流密度的平均值和标准差 (SD)，还捕获 SD 随时间和空间的传播。 SCTM 通过假设的高速公路走廊模拟和实证研究进行了测试。将仿真结果与从改进的小区传输模型 (MCTM) 的蒙特卡罗仿真 (MCS) 获得的流量密度的均值和标准差进行比较。选择南加州洛杉矶 210 号州际公路西 (I-210W) 约两英里的高速公路段进行实证研究。流量数据是从性能测量系统 (PeMS) 获得的。 SCTM 的随机参数根据 I-210W 的流量-密度经验数据进行校准。 SCTM和MCTM的MCS都经过测试。根据实证结果对两种方法的计算效率和准确性问题进行了讨论。数值模拟结果和实证结果均证实，与 MCS 相比，SCTM 能够准确估计高速公路密度的平均值和 SD。
The paper proposes a first-order macroscopic stochastic dynamic traffic model, namely the stochastic cell transmission model (SCTM), to model traffic flow density on freeway segments with stochastic demand and supply. The SCTM consists of five operational modes corresponding to different congestion levels of the freeway segment. Each mode is formulated as a discrete time bilinear stochastic system. A set of probabilistic conditions is proposed to characterize the probability of occurrence of each mode. The overall effect of the five modes is estimated by the joint traffic density which is derived from the theory of finite mixture distribution. The SCTM captures not only the mean and standard deviation (SD) of density of the traffic flow, but also the propagation of SD over time and space. The SCTM is tested with a hypothetical freeway corridor simulation and an empirical study. The simulation results are compared against the means and SDs of traffic densities obtained from the Monte Carlo Simulation (MCS) of the modified cell transmission model (MCTM). An approximately two-miles freeway segment of Interstate 210 West (I-210W) in Los Ageles, Southern California, is chosen for the empirical study. Traffic data is obtained from the Performance Measurement System (PeMS). The stochastic parameters of the SCTM are calibrated against the flow–density empirical data of I-210W. Both the SCTM and the MCS of the MCTM are tested. A discussion of the computational efficiency and the accuracy issues of the two methods is provided based on the empirical results. Both the numerical simulation results and the empirical results confirm that the SCTM is capable of accurately estimating the means and SDs of the freeway densities as compared to the MCS.