Applications and Development Workshop
April 8–9, 2010
Summary of Transims Deployment Activities in Atlanta
12300 West Dakota Ave.
Lakewood, CO, 80228
122 South Central Campus Dr.
Salt Lake City, UT 84112-0561
Phone: 720 963-3219
List of Authors
Eric Pihl, Kai Zuehlke
The deployment of TRANSIMS in Atlanta was driven by the need for more detailed information about operational characteristics of the transporation system under varying conditions, and to better understand sources of congestion in the Atlanta region. The current methodology for project selection involves use of a traditional four-step travel demand model, comparing vehicle hours traveled (VHT) for build and no-build scenarios. TRANSIMS was thought to offer improved analytical capabilities - particularly for smaller projects - because it can potentially do a better job of addressing bottlenecks, diurnals, peak spreading, and details on vehicle operations and emissions.
The project team, led by the Georgia Regional Transportation Authority with support from the Atlanta regional government and state environmental agency, directed their Transims deployment effort implemented Transims to evaluate a variety a set of illustrative transportation improvements of varying types, locations and sizes to better understand investment level and systems level impacts of planning and operations strategies. The scale of investments evaluated range from sub-area traffic operational improvements in a congested employment center to a managed lane scenario in a highly congested radial freeway corridor
The presentation will include an overview and discussion of the technical accomplishments and challenges of this deployment effort. Regional networks used for regional modeling were conflated with additional network detail that helped improve network accuracy, but also resulted in a considerable number of router stabilization iterations to achieve a reasonable set of plans for simulation. Initial variances with the regional model were observed in the vicinity of the regional airport, and and in congested suburban activities due in part to higher demand levels and increased network connectivity when compared to the regional model. These issues were dealt with in a comprehensive model calibration effort that will be discussed. Transims results and performance metrics will also be summarized, including a comparison of emissions estimated with an integrated Transims/MOVES model platform with emissions from the regional travel model with a link-based emissions rate model.
Eric has fourteen years of experience in the development and application of technical methods used to evaluate the economic, environmental, and land-use impacts of transportation investments. He began his career with the Atlanta MPO where he served a primary role in the refinement and application of the model to estimate emissions and travel impacts of the region's long range transportation plan and regionally-significant development projects. He carried his experience to a consulting practice where he was the technical lead on the update of Nashville's travel model to ensure its usefulness for AQ conformity determinations. Later experience gained with the US Environmental Protection Agency on model improvements to evaluate 'induced' travel impacts and emissions associated with brownfield redevelopment strategies provided opportunities to coordinate and link the academic and planning realms. Insights gained at EPA were applied as the technical lead at the Federal Transit Administration in his role as lead reviewer of travel models and forecasts for the New Starts investment program to ensure consistence with 'best practice'. He currently provides technical assistance on travel, traffic operations, and freight analysis models for the Federal Highway Administration Resource Center Planning Team. Eric is a member of the TRB committee on Transportation Planning Methods, and has served on expert review panels around the country. He has also served on a variety of TCRP and NCHRP peer panels spanning a highway and transit planning issues. He holds a MS in transportation engineering and a Master of City Planning from Georgia Tech.
Kai has helped the Georgia Regional Transportation Authority improve mobility, air quality, and land use practices for two years. He focuses on analyzing travel behavior, tracking air quality trends, and running models in support of program, project, and policy development. A member of the American Planning Association and the Institute of Transportation Engineers, Kai received M.S. Civil Engineering and Master of City and Regional Planning degrees from Georgia Tech, as well as a B.S. in Engineering Science and Mechanics from Virginia Tech.