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Metro's Research Center collects and analyzes transportation-related information to develop and maintain modeling tools for forecasting travel flows and emissions.

Transportation modeling overview
Last published: June 27, 2022
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Overview
Model development

Travel demand modeling and emission estimation

Travel demand models use data to predict transportation choices such as trip frequency, trip origins and destinations, types or modes of transportation and travel by time of day. Planners and policy makers use these models to analyze the effects of such factors as increased population and employment, changes in development patterns, transportation infrastructure improvements, transit service changes and regional transportation policy impacts on travel behavior.

The Federal Highway Administration, Federal Transit Administration and U.S. Environmental Protection Agency require that project analysis be carried out using methods and modeling tools that meet certain guidelines. Metro’s travel demand models are regularly reviewed by the appropriate federal agencies and expert panels to ensure that they meet federal guidelines and meet or exceed the standard practices of other travel demand models used throughout the country.

Metro currently maintains a four-step trip based travel behavior model and is developing a next generation dynamic tour based model. The program also uses federally required models for the analysis of air quality and vehicle emissions and of transit projects seeking federal funding.

Current modeling tools used in transportation research and modeling have addressed the needs of regional decision makers for many years. However, given the increasing complexity of problem statements and study environments, tool enhancements are needed so that the models may remain useful in future analytical processes. Metro is undertaking these model development projects to meet the future needs of decision makers.

Dynamic tour based model

Metro and Portland State University have developed a partnership to develop a dynamic tour based model. The model will estimate the travel patterns for an individual, and travel will be linked to form tours. It will include a strong temporal component – one that will evaluate the "instantaneous" characteristics that are present at the time of a travel choice. Destination, modal, time of day and occupancy decisions will be addressed in the model.

Dynamic traffic assignment

Efforts are underway to implement a new assignment algorithm in the region. The dynamic assignment will provide a much more rigorous tool to assess congestion in terms of lane occupancy, queue length, duration of peak, speeds and volumes in short time period increments, and improved visualization.

Enhancement of transit models

In 2009, a contract was awarded to a contractor to measure the perception of time for the transit rider and to collect travel data for several special market areas (park and ride transit patrons, and hotel visitors to the central city). This data will be used to enhance the travel model’s ability to produce information about these special market areas.

Bicycle travel analysis tools

During 2009, Metro collaborated with Portland State University to fund innovative bike research. Using bike path data derived from GPS, a path finding algorithm was developed that reflects the preference of the rider toward various infrastructure attributes. The enriched process will allow a fuller communication of path desirability to the travel demand model. In 2010, the information will be used to re-estimate the mode choice model to capture the effects of the path attributes on the bicycle mode choice.

Household travel behavior survey

Household surveys provide the behavioral data that form the foundation of travel demand models. These surveys provide both a snapshot of current travel behavior, and an understanding of how factors such as age, income, children, car ownership, accessibility, and congestion influence household activities, time usage, and travel choices. In 2011, Metro conducted a survey of 4,800 households throughout Clackamas, Multnomah, and Washington counties. The survey is part of a multi-agency collaborative effort that ultimately included about 18,000 households throughout Oregon and 1,650 households in Southwest Washington.