May 23, 2019


A New Web Tool to Calculate Induced Travel


10:00am - 11:00am


1605 Tilia, Room 1103, West Village

Biographical Sketch

Jamey Volker is a PhD candidate in the Transportation Technology and Policy program at UC Davis. He studies people’s travel behaviors and residential location choices, and the impacts of regulation on land use.

Dr. Susan Handy is the Director of the National Center for Sustainable Transportation, and a professor in the UC Davis Department of Environmental Science and Policy. Dr. Handy is well known for her research on active transportation, the impacts of land use on travel behavior, and strategies for reducing automobile dependence.
Guest Respondents:

Chris Ganson is the Senior Advisor for Transportation at the Governor’s Office of Planning and Research. He is the technical lead implementing SB 743 and serves as OPR’s lead on automated vehicles. Chris previously held positions at the Lawrence Berkeley National Laboratory, the World Resources Institute, and US EPA Region 9. Chris holds master’s degrees in City Planning and Transportation Engineering, and a Bachelor’s Degree in Environmental Sciences, all from UC Berkeley.

Gordon Garry is currently mostly retired after a professional career of 40 years. He keeps an active role professionally through various projects with government agencies and NGOs. From 1990 to 2017 he was a senior staff member at the Sacramento Area Council of Governments. He developed and managed an increasing array of data and forecasting programs to support the agency’s transportation, air quality, land use planning, and climate change efforts. He was responsible for modeling projections and analyses in these areas that meet local, state, and Federal planning requirements.

Attempts to address traffic congestion commonly rely on increasing roadway capacity, e.g. by building new roadways or adding lanes to existing facilities. But studies continue to show that adding capacity is at best a temporary fix: adding roadway capacity in congested areas actually increases network-wide vehicle miles traveled (VMT) by a nearly equivalent proportion within a few years, which reduces or negates any initial congestion relief. That increase in VMT is called “induced travel.” The induced travel effect is explained by bedrock economic principles of supply and demand: adding roadway capacity reduces travel time; and as that effective “price” of driving goes down, the quantity of driving increases. The magnitude of that increase is commonly measured as the elasticity of VMT with respect to lane miles. Studies generally show that a 10-percent increase in roadway capacity is likely to increase network-wide VMT by 6 to 10 percent (an elasticity of 0.6 to 1.0). Yet methods of calculating project-level induced travel frequently vary and are often opaquely explained in transportation impact studies. NCST researchers developed a web-based induced VMT calculator to help with that.

This webinar will:
* Give an overview of the induced travel concept;
* Summarize the academic research on induced travel elasticities;
* Introduce the new induced VMT calculator developed by NCST researchers; and
* Provide discussion on the calculator from two California transportation planning and policy experts.

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