Incorporating Within-Day Transitions in the Simultaneous Off-line Estimation of Dynamic Origin-Destination Flows without Assignment Matrices

An off-line methodology for simultaneously estimating dynamic origin-destination matrices without using assignment matrices that incorporates within day transition equations is presented. The proposed formulation and solution approach extend a calibration method recently developed that directly uses the output of any network loading model (such as a dynamic traffic assignment or simulation model) so that the complex relationships between OD flows and model outputs are accurately captured (as opposed to the more common method of approximate linear relationships based on the assignment matrix). The paper extends the original formulation by incorporating spatial and temporal relationships among various OD flows (transition equations). These transition equations link OD flow variables across time intervals in such a way that known structural demand patterns can be preserved in the new estimates. Such transition equations, while common in the context of real-time OD flows, complicate the off-line simultaneous estimation of OD flows and have not been used to their full potential in the past. The approach is demonstrated through a case study.