Dynamic, integrated model system : Sacramento-area application. Volume 1: summary report.

Author(s)
Cambridge Systematics, Inc. Sacramento Area Council of Governments University of Arizona University of Illinois, Chicago Sonoma Technology, Inc. & Fehr and Peers
Year
Abstract

Travel demand models have been used for more than half a century to determine the need for and estimate the usage of proposed new highway and transit systems. The majority of such models use Traffic Analysis Zones to aggregate demographic data and estimate interzonal travel demand for large time blocks (such as morning peak period). The interzonal demand is assigned to a link and node network to estimate likely roadway volumes. Activity-based travel demand models are based on the disaggregate travel activity of individual travelers, not the aggregate behavior of all the travelers in a zone. They have the potential to better simulate behaviors such as time-of-day choice, route choice, mode choice, and trip chaining. As with real travelers, information on the state of the network is needed to make choices. The feedback loop from the network assignment may cause a simulated “traveler” to change route, time of day, or mode in response to network congestion. The model set iterates until convergence is reached–travel volumes and modes are stable after successive iterations. Activity-based models have been available for some time but are not widely used in production planning work. Dynamic traffic assignment models are network simulation tools that represent network travel conditions. Such simulation models are used for subarea traffic analysis but have not been linked to a demographically based demand model and used at the urban-area scale. This project integrated the supply and demand side of transportation demand forecasting in order to test operational improvements to the highway system as well as capacity enhancements. The Sacramento Area Council of Governments (SACOG) used the model set to test transportation alternatives. The results are proof-of-concept in nature. The integrated model works and demonstrates potential improved sensitivity to policies that affect regional travel. However, the model did not converge as hoped, so it was not possible to fully calibrate it prior to testing by SACOG. The integrated model sets built for this project are available as a basis for implementing a similar approach in other urban areas. (Author/publisher)

Publication

Library number
20141136 ST [electronic version only]
Source

Washington, D.C., Transportation Research Board TRB, 2014, 97 p., 13 ref.; The Second Strategic Highway Research Program SHRP 2 ; Report S2-C10B-RW-1 - ISBN 978-0-309-27382-4

Publication (link)

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