California Air Resources Board

Principal Investigator/Author: Bruce Appleyard, Elisa Barbour

Contractor: San Diego State University and University of California, Davis

Sub-contractors: University of Utah

Contract Number: 21STC015

Project Status: Active

Relevant CARB Programs: Sustainable Communities & Climate Protection Program, California Climate Investments, Community Solutions, Local Actions for Climate Change, Low Carbon Transportation Investments and Air Quality Improvement Program, Research Planning, Sustainable Transportation Equity Project (STEP)

Topic Areas: Sustainable Communities,Research & Sustainable Communities, Sustainable Community Strategies (SCS), Climate Change, Vehicle Miles Traveled (VMT) Reduction & Climate Goals, California Climate Investments, Land Use & Transportation Research, Transit, emission reduction strategies, mitigation, behavioral economics

Research Summary:

This project summarizes the current research and develops a tool to estimate the indirect impacts of transit investment on local vehicle miles traveled (VMT), greenhouse gas (GHG) emissions, and housing production and affordability.

This will support State, regional, and local policy efforts to promote more efficient development patterns. While State policies and programs aim to promote efficient development patterns, the methods used by state, regional, and local agencies to quantify the benefits of transit investments tend to focus on direct ridership effects and often overlook  the “indirect effects” of these investments. Agencies overlook the indirect effects because of lack of adequate methodologies, which can underestimate the positive effects of transit investments, especially over the long run, towards reducing VMT and GHG emissions. To address this issue, this project will develop methodologies for estimating indirect effects of transit.

This project will first summarize the current literature and research on the indirect impacts of transit investment on the built environment and associated impacts on travel behavior (e.g., mode choice), as well as their effects on GHG emissions, VMT, and housing production and affordability. Next, the project will use this information to develop a white paper and a tool capable of estimating the potential indirect benefits of transit investments at the transit station level, which is the area within one mile of a transit station or stop.

Keywords: communities, equity, sustainable communities and health, environmental justice, reducing disparities, racial equity, social equity, climate change, behavioral economics, new housing, Vehicle Miles Traveled (VMT), greenhouse gas reduction strategies, equitable and affordable housing, transportation and land use, sustainable neighborhoods, redlining, disadvantaged communities, Scoping Plan, climate actions, equitable climate policy, transit, transit investments, housing, built environment, indirect effects, indirect impacts, travel behavior, housing, affordability