Affordable Housing Trip Generation Strategies and Rates

Kelly Clifton, Portland State University


  • Kristina Currans, University of Arizona
  • Susan Handy, University of California, Davis
  • Robert Schneider, UW - Milwaukee


Assessment and mitigation of transportation impacts based on travel demand is required by state, federal, and local laws in California. Determining trip generation is typically the first step in preparing these transportation impact analyses, and current industry standard practice relies on trip rates published by the Institute of Transportation Engineers (ITE). However, ITE protocols emphasize vehicle trip rates without sensitivity to urban context or socioeconomic characteristics, which can exaggerate the impact of certain land uses like affordable housing developments, ultimately increasing mitigation fees. Updating trip generation methodologies is critical given the increasing demand for affordable housing, especially in urban contexts. This study builds on previous trip generation research in California and elsewhere, and examines trip generation rates for affordable housing locations in Los Angeles and San Francisco Bay Area regions using a multi-method research design. Data were collected, assembled, and analyzed to provide a robust picture of trip making, vehicle ownership, and mode use as a function of development characteristics, household demographics, and urban setting. Results show a strong association between these factors and trip generation, and reiterate the need to revise current industry standard practices. A discussion of policy implications, as well as suggested next steps in research and development, are provided with this in mind.

Project Details

Project Type:
Project Status:
End Date:
September 14,2018
UTC Grant Cycle:
non-UTC project

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