Dynamic Traffic Assignment: A Primer

Transportation Research Board is to provide leadership in transportation innovation and progress through research and information exchange, conducted within a setting that is objective, interdisciplinary, and multimodal. The Transportation Research Board is distributing this circular to make the information contained herein available for use by individual practitioners in state and local transportation agencies, researchers in academic institutions, and other members of the transportation research community. The information in this circular was taken directly from the submission of the authors. Preface ransportation planners and traffic engineers are faced nowadays with immense modeling challenges arising from several emerging policy, planning, and engineering developments. Hence, interest has grown in applying traffic analysis tools capable of analyzing travel activities and dynamic network performance for a corridor or region over peak hours or even extended daily hours. Now, after decades of research and intensive market readiness developments, dynamic traffic assignment (DTA) models have become a viable modeling option. DTA models supplemental existing travel forecasting models and microscopic traffic simulation models. Travel forecasting models represent the static regional travel analysis capability, whereas microscopic traffic simulation models are superior for dynamic corridor-level travel analysis. DTA models fill in the gap by enabling dynamic traffic to be modeled at a range of scales from the corridor level to the regional with expanded and unique functional capabilities enabled by the DTA methodology. The motivations for the TRB Network Modeling Committee (ADB30) in developing this primer were to provide neutral and factual information about DTA, to facilitate informed decision making by practitioners in planning or managing a DTA modeling activity, and to engage practitioners with educational material about modeling exercises and interpretations of results related to DTA. The objectives of this primer therefore are to • Explain the basic concepts of DTA and various DTA definitions and implementations, • Highlight the types of transportation analysis applications for which DTA models could be found useful, • Provide information about how to select a DTA model that best serves the intended application, • Provide information regarding planning for and executing a DTA traffic analysis activity, and • Describe the general DTA modeling procedure and modeling issues that may concern a model user. This effort represents a first step in the committee's continuing commitment to facilitate development of practical analysis procedures in the DTA area and to improve communication among DTA researchers, developers, and user communities. AUTHORS' ACKNOWLEDGMENTS This publication is the result …