The Induced Travel Calculator and Its Applications

Research Team: Jamey Volker (lead) and Susan Handy

UC Campus(es): UC Davis

Problem Statement: Attempts to address traffic congestion commonly rely on increasing roadway capacity (e.g., building new roadways or adding lanes to existing facilities); however, studies consistently show that adding roadway capacity in congested areas increases network-wide vehicle miles traveled (VMT) by a nearly equivalent proportion within a few years. The increase in VMT from increasing roadway capacity is called “induced travel.” To assist public agencies in estimating the amount of induced travel that may result from a capacity expansion project, UC Davis researchers in a previous project developed the Induced Travel Calculator. This calculator allows users to estimate the amount of VMT induced on an annual basis as a result of expanding the capacity of roadways managed by the Caltrans in California’s urbanized counties. Caltrans is considering whether to recommend the use of the Induced Travel Calculator in its guidance for the evaluation of environmental impacts for highway projects under the California Environmental Quality Act (CEQA).

Project Description: This project provided technical assistance to Caltrans and other agencies using or contemplating the use of the Induced Travel Calculator. As a part of the project, the team explored possible improvements to the calculator and developed a plan for implementing the improvements. This project supported the development of a tool that can be used to support public agencies calculating the induced travel impacts of roadway expansion projects.

Status: Completed

Budget: $25,000

Project Partner(s): California Department of Transportation

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