Evaluation of Horizontal and Vertical Queueing Models in Relation to Observed Trajectory Data in a Signalized Urban Traffic Network

While the Cell Transmission Model (CTM) is generally accepted as a standard representation of traffic flows on freeways with long links and uninterrupted flows, less is known about the accuracy of CTM or other macroscopic queueing models on urban road networks with short links and frequent flow blockages due to signal control. In fact, almost all existing validations of CTM focus on modeling freeways. In this paper, the authors aim to provide evidence towards selecting the appropriate queueing model dynamics for use in analysis and control of a large-scale network of signalized traffic intersections. They introduce a new vertical queueing dynamics called the Vertical Cell Model (VCM) that incorporates a representation of link transit time and finite queue capacity. The linear link model of VCM provides an attractive new alternative to CTM for practical network-wide estimation and control procedures. The authors then compare the link outflow and density outputs of both VCM and CTM to a set of high fidelity ground-truth observations on a multi-intersection segment of an existing urban roadway. Ultimately they provide a validation of both CTM and VCM for use in arterial networks which have minimal observed over-saturation. The development and validation of VCM is a first step toward a new control-theoretic approach to the operations of signalized intersections in a large-scale network.